#13982 Python: Tighten Instance.launch/find return type and drop dead None checks

Instance.launch and Instance.find now always either return a connected
Instance or raise RipsError, so their return type narrows from
Optional[Instance] to Instance. In launch(), the unreachable `if pid:`
guard around the Popen result and the trailing `return None` are
removed; the only failure paths raise RipsError.

Update the PythonExamples that previously branched on a None return:
- Drop `if resinsight is None: exit(1)` style guards and `if resinsight
  is not None:` wrappers; dedent the body where applicable.
- export_corner_point_grid.py used the None check as a fallback to
  launch ResInsight; rewrite as try/except rips.RipsError so the
  fallback still works.
- instance_example.py is repurposed as a try/except example for
  reporting connection failure.

GrpcInterface/Python/rips/PythonExamples/basic_operations/all_cases.py

@@ -8,32 +8,32 @@ import rips
 
 # Connect to ResInsight
 resinsight = rips.Instance.find()
-if resinsight is not None:
-    # Get a list of all cases
-    cases = resinsight.project.cases()
 
-    print("Got " + str(len(cases)) + " cases: ")
-    for case in cases:
-        print("Case id: " + str(case.id))
-        print("Case name: " + case.name)
-        print("Case type: " + case.__class__.__name__)
-        print("Case file name: " + case.file_path)
-        print("Case reservoir bounding box:", case.reservoir_boundingbox())
+# Get a list of all cases
+cases = resinsight.project.cases()
 
-        timesteps = case.time_steps()
-        for t in timesteps:
-            print("Year: " + str(t.year))
-            print("Month: " + str(t.month))
+print("Got " + str(len(cases)) + " cases: ")
+for case in cases:
+    print("Case id: " + str(case.id))
+    print("Case name: " + case.name)
+    print("Case type: " + case.__class__.__name__)
+    print("Case file name: " + case.file_path)
+    print("Case reservoir bounding box:", case.reservoir_boundingbox())
 
-        if isinstance(case, rips.EclipseCase):
-            print("Getting coarsening info for case: ", case.name, case.id)
-            coarsening_info = case.coarsening_info()
-            if coarsening_info:
-                print("Coarsening information:")
+    timesteps = case.time_steps()
+    for t in timesteps:
+        print("Year: " + str(t.year))
+        print("Month: " + str(t.month))
 
-            for c in coarsening_info:
-                print(
-                    "[{}, {}, {}] - [{}, {}, {}]".format(
-                        c.min.x, c.min.y, c.min.z, c.max.x, c.max.y, c.max.z
-                    )
+    if isinstance(case, rips.EclipseCase):
+        print("Getting coarsening info for case: ", case.name, case.id)
+        coarsening_info = case.coarsening_info()
+        if coarsening_info:
+            print("Coarsening information:")
+
+        for c in coarsening_info:
+            print(
+                "[{}, {}, {}] - [{}, {}, {}]".format(
+                    c.min.x, c.min.y, c.min.z, c.max.x, c.max.y, c.max.z
                 )
+            )

GrpcInterface/Python/rips/PythonExamples/basic_operations/instance_example.py

@@ -3,9 +3,8 @@
 #######################################
 import rips
 
-resinsight = rips.Instance.find()
-
-if resinsight is None:
-    print("ERROR: could not find ResInsight")
-else:
+try:
+    resinsight = rips.Instance.find()
     print("Successfully connected to ResInsight")
+except rips.RipsError as e:
+    print(f"ERROR: could not find ResInsight: {e}")

GrpcInterface/Python/rips/PythonExamples/basic_operations/selected_cases.py

@@ -8,11 +8,10 @@
 import rips
 
 resinsight = rips.Instance.find()
-if resinsight is not None:
-    cases = resinsight.project.selected_cases()
+cases = resinsight.project.selected_cases()
 
-    print("Got " + str(len(cases)) + " cases: ")
-    for case in cases:
-        print(case.name)
-        for property in case.available_properties(rips.PropertyType.DYNAMIC_NATIVE):
-            print(property)
+print("Got " + str(len(cases)) + " cases: ")
+for case in cases:
+    print(case.name)
+    for property in case.available_properties(rips.PropertyType.DYNAMIC_NATIVE):
+        print(property)

GrpcInterface/Python/rips/PythonExamples/case_and_grid_operations/export_corner_point_grid.py

@@ -34,9 +34,10 @@ def validate_grid_dimensions(coord_array, zcorn_array, actnum_array, nx, ny, nz)
 
 
 def main():
-    # Connect to ResInsight
-    resinsight = rips.Instance.find()
-    if resinsight is None:
+    # Connect to ResInsight, launching it if no existing instance is found.
+    try:
+        resinsight = rips.Instance.find()
+    except rips.RipsError:
         print("Starting ResInsight...")
         resinsight = rips.Instance.launch(console=True)
 

GrpcInterface/Python/rips/PythonExamples/case_and_grid_operations/fault_distance.py

@@ -5,8 +5,6 @@
 import rips
 
 resinsight = rips.Instance.find()
-if resinsight is None:
-    exit(1)
 
 cases = resinsight.project.cases()
 if len(cases) == 0:

GrpcInterface/Python/rips/PythonExamples/case_and_grid_operations/polygon_region_from_project.py

@@ -34,9 +34,6 @@ def point_in_polygon_2d(px, py, polygon_xy):
 
 
 resinsight = rips.Instance.find()
-if resinsight is None:
-    print("No ResInsight instance found")
-    exit()
 
 cases = resinsight.project.cases()
 if not cases:

GrpcInterface/Python/rips/PythonExamples/case_and_grid_operations/selected_cells.py

@@ -6,63 +6,62 @@
 import rips
 
 resinsight = rips.Instance.find()
-if resinsight is not None:
-    cases = resinsight.project.cases()
+cases = resinsight.project.cases()
 
-    print("Got " + str(len(cases)) + " cases: ")
-    for case in cases:
-        print(case.name)
-        cells = case.selected_cells()
-        print("Found " + str(len(cells)) + " selected cells")
+print("Got " + str(len(cases)) + " cases: ")
+for case in cases:
+    print(case.name)
+    cells = case.selected_cells()
+    print("Found " + str(len(cells)) + " selected cells")
 
-        time_step_info = case.time_steps()
+    time_step_info = case.time_steps()
 
-        for idx, cell in enumerate(cells):
+    for idx, cell in enumerate(cells):
+        print(
+            "Selected cell: [{}, {}, {}] grid: {}".format(
+                cell.ijk.i + 1, cell.ijk.j + 1, cell.ijk.k + 1, cell.grid_index
+            )
+        )
+
+        # Get the grid and dimensions
+        grid = case.grids()[cell.grid_index]
+        dimensions = grid.dimensions()
+
+        # Map ijk to cell index
+        cell_index = (
+            dimensions.i * dimensions.j * cell.ijk.k
+            + dimensions.i * cell.ijk.j
+            + cell.ijk.i
+        )
+
+        # Print the cell center
+        cell_centers = grid.cell_centers()
+        cell_center = cell_centers[cell_index]
+        print(
+            "Cell center: [{}, {}, {}]".format(
+                cell_center.x, cell_center.y, cell_center.z
+            )
+        )
+
+        # Print the cell corners
+        cell_corners = grid.cell_corners()[cell_index]
+        print("Cell corners:")
+        print("c0:\n" + str(cell_corners.c0))
+        print("c1:\n" + str(cell_corners.c1))
+        print("c2:\n" + str(cell_corners.c2))
+        print("c3:\n" + str(cell_corners.c3))
+        print("c4:\n" + str(cell_corners.c4))
+        print("c5:\n" + str(cell_corners.c5))
+        print("c6:\n" + str(cell_corners.c6))
+        print("c7:\n" + str(cell_corners.c7))
+
+        for tidx, timestep in enumerate(time_step_info):
+            # Read the full SOIL result for time step
+            soil_results = case.selected_cell_property(
+                rips.PropertyType.DYNAMIC_NATIVE, "SOIL", tidx
+            )
             print(
-                "Selected cell: [{}, {}, {}] grid: {}".format(
-                    cell.ijk.i + 1, cell.ijk.j + 1, cell.ijk.k + 1, cell.grid_index
+                "SOIL: {} ({}.{}.{})".format(
+                    soil_results[idx], timestep.year, timestep.month, timestep.day
                 )
             )
-
-            # Get the grid and dimensions
-            grid = case.grids()[cell.grid_index]
-            dimensions = grid.dimensions()
-
-            # Map ijk to cell index
-            cell_index = (
-                dimensions.i * dimensions.j * cell.ijk.k
-                + dimensions.i * cell.ijk.j
-                + cell.ijk.i
-            )
-
-            # Print the cell center
-            cell_centers = grid.cell_centers()
-            cell_center = cell_centers[cell_index]
-            print(
-                "Cell center: [{}, {}, {}]".format(
-                    cell_center.x, cell_center.y, cell_center.z
-                )
-            )
-
-            # Print the cell corners
-            cell_corners = grid.cell_corners()[cell_index]
-            print("Cell corners:")
-            print("c0:\n" + str(cell_corners.c0))
-            print("c1:\n" + str(cell_corners.c1))
-            print("c2:\n" + str(cell_corners.c2))
-            print("c3:\n" + str(cell_corners.c3))
-            print("c4:\n" + str(cell_corners.c4))
-            print("c5:\n" + str(cell_corners.c5))
-            print("c6:\n" + str(cell_corners.c6))
-            print("c7:\n" + str(cell_corners.c7))
-
-            for tidx, timestep in enumerate(time_step_info):
-                # Read the full SOIL result for time step
-                soil_results = case.selected_cell_property(
-                    rips.PropertyType.DYNAMIC_NATIVE, "SOIL", tidx
-                )
-                print(
-                    "SOIL: {} ({}.{}.{})".format(
-                        soil_results[idx], timestep.year, timestep.month, timestep.day
-                    )
-                )

GrpcInterface/Python/rips/PythonExamples/surfaces_and_visualization/create_polygon.py

@@ -8,42 +8,42 @@ import rips
 
 # Connect to ResInsight
 resinsight = rips.Instance.find()
-if resinsight is not None:
-    # Get a list of all cases
-    cases = resinsight.project.cases()
 
-    for c in cases:
-        print("Case name: " + c.name)
+# Get a list of all cases
+cases = resinsight.project.cases()
 
-        # create a polygon which is same a the bounding box in x and y.
-        # depth is set to middle of the bounding box
-        bbox = c.reservoir_boundingbox()
-        depth = bbox.max_z - ((bbox.max_z - bbox.min_z) / 2.0)
+for c in cases:
+    print("Case name: " + c.name)
 
-        coordinates = []
-        coordinates.append([bbox.min_x, bbox.min_y, depth])
-        coordinates.append([bbox.max_x, bbox.min_y, depth])
-        coordinates.append([bbox.max_x, bbox.max_y, depth])
-        coordinates.append([bbox.min_x, bbox.max_y, depth])
+    # create a polygon which is same a the bounding box in x and y.
+    # depth is set to middle of the bounding box
+    bbox = c.reservoir_boundingbox()
+    depth = bbox.max_z - ((bbox.max_z - bbox.min_z) / 2.0)
 
-        polygon_collection = resinsight.project.descendants(rips.PolygonCollection)[0]
-        p = polygon_collection.create_polygon(
-            name="{} bounding box".format(c.name), coordinates=coordinates
-        )
-        print("Coordinates for {}:".format(p.name))
-        for coord in p.coordinates:
-            print(coord)
+    coordinates = []
+    coordinates.append([bbox.min_x, bbox.min_y, depth])
+    coordinates.append([bbox.max_x, bbox.min_y, depth])
+    coordinates.append([bbox.max_x, bbox.max_y, depth])
+    coordinates.append([bbox.min_x, bbox.max_y, depth])
 
-        # Customize appearance
-        appearance = p.appearance()
-        if appearance is not None:
-            appearance.line_color = "#ff0000"
-            appearance.line_thickness = 5
-            appearance.show_spheres = True
-            appearance.sphere_color = "#0000ff"
-            appearance.update()
-            print(
-                "Appearance updated: line_color={}, line_thickness={}".format(
-                    appearance.line_color, appearance.line_thickness
-                )
+    polygon_collection = resinsight.project.descendants(rips.PolygonCollection)[0]
+    p = polygon_collection.create_polygon(
+        name="{} bounding box".format(c.name), coordinates=coordinates
+    )
+    print("Coordinates for {}:".format(p.name))
+    for coord in p.coordinates:
+        print(coord)
+
+    # Customize appearance
+    appearance = p.appearance()
+    if appearance is not None:
+        appearance.line_color = "#ff0000"
+        appearance.line_thickness = 5
+        appearance.show_spheres = True
+        appearance.sphere_color = "#0000ff"
+        appearance.update()
+        print(
+            "Appearance updated: line_color={}, line_thickness={}".format(
+                appearance.line_color, appearance.line_thickness
             )
+        )

GrpcInterface/Python/rips/PythonExamples/surfaces_and_visualization/create_regular_surface.py

@@ -34,58 +34,56 @@ resinsight = rips.Instance.find()
 
 project = resinsight.project
 
+# Get a list of all cases
+cases = resinsight.project.cases()
 
-if resinsight is not None:
-    # Get a list of all cases
-    cases = resinsight.project.cases()
+for c in cases:
+    bbox = c.reservoir_boundingbox()
+    depth = bbox.max_z - ((bbox.max_z - bbox.min_z) / 2.0)
 
-    for c in cases:
-        bbox = c.reservoir_boundingbox()
-        depth = bbox.max_z - ((bbox.max_z - bbox.min_z) / 2.0)
+    origin_x = bbox.min_x
+    origin_y = bbox.min_y
 
-        origin_x = bbox.min_x
-        origin_y = bbox.min_y
+    name = "{} surface".format(c.name)
 
-        name = "{} surface".format(c.name)
+    nx = 200
+    ny = 100
 
-        nx = 200
-        ny = 100
+    increment_x = (bbox.max_x - bbox.min_x) / float(nx)
+    increment_y = (bbox.max_y - bbox.min_y) / float(ny)
 
-        increment_x = (bbox.max_x - bbox.min_x) / float(nx)
-        increment_y = (bbox.max_y - bbox.min_y) / float(ny)
+    surface_collection = resinsight.project.descendants(rips.SurfaceCollection)[0]
 
-        surface_collection = resinsight.project.descendants(rips.SurfaceCollection)[0]
+    # Create a surface at a given depth
+    s = surface_collection.new_regular_surface(
+        name=name,
+        origin_x=origin_x,
+        origin_y=origin_y,
+        depth=-depth,
+        nx=nx,
+        ny=ny,
+        increment_x=increment_x,
+        increment_y=increment_y,
+    )
 
-        # Create a surface at a given depth
-        s = surface_collection.new_regular_surface(
-            name=name,
-            origin_x=origin_x,
-            origin_y=origin_y,
-            depth=-depth,
-            nx=nx,
-            ny=ny,
-            increment_x=increment_x,
-            increment_y=increment_y,
-        )
+    # Rotate the resulting surface
+    s.rotation = 45.0
+    s.update()
 
-        # Rotate the resulting surface
-        s.rotation = 45.0
-        s.update()
+    # Add one property
+    s.set_property("first_property", create_x_surface(nx, ny))
 
-        # Add one property
-        s.set_property("first_property", create_x_surface(nx, ny))
+    # Add a wave surface
+    s.set_property("wave", create_wave_surface(nx, ny))
 
-        # Add a wave surface
-        s.set_property("wave", create_wave_surface(nx, ny))
+    wave_values = s.get_property("wave")
+    print(
+        f"Retrieved {len(wave_values)} wave property values, min={min(wave_values):.2f}, max={max(wave_values):.2f}"
+    )
 
-        wave_values = s.get_property("wave")
-        print(
-            f"Retrieved {len(wave_values)} wave property values, min={min(wave_values):.2f}, max={max(wave_values):.2f}"
-        )
+    # List available properties
+    props = s.available_properties()
+    print(f"Available properties: {props}")
 
-        # List available properties
-        props = s.available_properties()
-        print(f"Available properties: {props}")
-
-        # Use the wave as depth for the surface
-        s.set_property_as_depth("wave")
+    # Use the wave as depth for the surface
+    s.set_property_as_depth("wave")

GrpcInterface/Python/rips/PythonExamples/surfaces_and_visualization/view_example.py

@@ -8,23 +8,21 @@ import rips
 # Connect to ResInsight instance
 resinsight = rips.Instance.find()
 
-# Check if connection worked
-if resinsight is not None:
-    # Get a list of all cases
-    cases = resinsight.project.cases()
-    for case in cases:
-        # Get a list of all views
-        views = case.views()
-        for view in views:
-            # Set some parameters for the view
-            view.show_grid_box = not view.show_grid_box
-            view.background_color = "#3388AA"
-            # Update the view in ResInsight
-            view.update()
-        # Clone the first view
-        new_view = views[0].clone()
-        new_view.background_color = "#FFAA33"
-        new_view.update()
-        view.show_grid_box = False
-        view.set_visible(False)
+# Get a list of all cases
+cases = resinsight.project.cases()
+for case in cases:
+    # Get a list of all views
+    views = case.views()
+    for view in views:
+        # Set some parameters for the view
+        view.show_grid_box = not view.show_grid_box
+        view.background_color = "#3388AA"
+        # Update the view in ResInsight
         view.update()
+    # Clone the first view
+    new_view = views[0].clone()
+    new_view.background_color = "#FFAA33"
+    new_view.update()
+    view.show_grid_box = False
+    view.set_visible(False)
+    view.update()

GrpcInterface/Python/rips/PythonExamples/wells_and_fractures/accumulated_perforation_length.py

@@ -11,8 +11,6 @@ import sys
 
 # Connect to ResInsight
 resinsight = rips.Instance.find()
-if resinsight is None:
-    sys.exit("ResInsight is not running. Please start ResInsight and try again.")
 
 # Get a list of all wells
 cases = resinsight.project.cases()

GrpcInterface/Python/rips/PythonExamples/wells_and_fractures/all_simulation_wells.py

@@ -8,29 +8,29 @@ import rips
 
 # Connect to ResInsight
 resinsight = rips.Instance.find()
-if resinsight is not None:
-    # Get a list of all wells
-    cases = resinsight.project.cases()
 
-    for case in cases:
-        print("Case id: " + str(case.id))
-        print("Case name: " + case.name)
+# Get a list of all wells
+cases = resinsight.project.cases()
 
-        timesteps = case.time_steps()
-        sim_wells = case.simulation_wells()
-        for sim_well in sim_wells:
-            print("Simulation well: " + sim_well.name)
+for case in cases:
+    print("Case id: " + str(case.id))
+    print("Case name: " + case.name)
 
-            for tidx, timestep in enumerate(timesteps):
-                status = sim_well.status(tidx)
-                cells = sim_well.cells(tidx)
-                print(
-                    "timestep: "
-                    + str(tidx)
-                    + " type: "
-                    + status.well_type
-                    + " open: "
-                    + str(status.is_open)
-                    + " cells:"
-                    + str(len(cells))
-                )
+    timesteps = case.time_steps()
+    sim_wells = case.simulation_wells()
+    for sim_well in sim_wells:
+        print("Simulation well: " + sim_well.name)
+
+        for tidx, timestep in enumerate(timesteps):
+            status = sim_well.status(tidx)
+            cells = sim_well.cells(tidx)
+            print(
+                "timestep: "
+                + str(tidx)
+                + " type: "
+                + status.well_type
+                + " open: "
+                + str(status.is_open)
+                + " cells:"
+                + str(len(cells))
+            )

GrpcInterface/Python/rips/PythonExamples/wells_and_fractures/all_wells.py

@@ -8,10 +8,10 @@ import rips
 
 # Connect to ResInsight
 resinsight = rips.Instance.find()
-if resinsight is not None:
-    # Get a list of all wells
-    wells = resinsight.project.well_paths()
 
-    print("Got " + str(len(wells)) + " wells: ")
-    for well in wells:
-        print("Well name: " + well.name)
+# Get a list of all wells
+wells = resinsight.project.well_paths()
+
+print("Got " + str(len(wells)) + " wells: ")
+for well in wells:
+    print("Well name: " + well.name)

GrpcInterface/Python/rips/PythonExamples/wells_and_fractures/append_lateral_to_well.py

@@ -1,8 +1,6 @@
 import rips
 
 resinsight = rips.Instance.find()
-if resinsight is None:
-    raise RuntimeError("No running ResInsight instance found on the expected ports.")
 
 # Create a modeled well path and add well path targets
 # The coordinates are based on the Norne case

GrpcInterface/Python/rips/PythonExamples/wells_and_fractures/completion_data.py

@@ -17,8 +17,6 @@ def fieldValueOrDefaultText(grpc_object, optional_field_name: str):
 
 # Connect to ResInsight
 resinsight = rips.Instance.find()
-if resinsight is None:
-    exit(1)
 
 # Get a list of all wells
 wells = resinsight.project.well_paths()

GrpcInterface/Python/rips/PythonExamples/wells_and_fractures/duplicate_well.py

@@ -9,14 +9,14 @@ import rips
 
 # Connect to ResInsight
 resinsight = rips.Instance.find()
-if resinsight is not None:
-    # Get a list of all wells
-    wells = resinsight.project.well_paths()
 
-    print("Got " + str(len(wells)) + " wells: ")
-    for well in wells:
-        print("Well name: " + well.name)
+# Get a list of all wells
+wells = resinsight.project.well_paths()
 
-        # will only work for editable well paths (ModeledWellPath)
-        new_well = well.duplicate()
-        print("New Well name: " + new_well.name)
+print("Got " + str(len(wells)) + " wells: ")
+for well in wells:
+    print("Well name: " + well.name)
+
+    # will only work for editable well paths (ModeledWellPath)
+    new_well = well.duplicate()
+    print("New Well name: " + new_well.name)

GrpcInterface/Python/rips/PythonExamples/wells_and_fractures/export_well_path_trajectory_with_properties.py

@@ -23,39 +23,39 @@ def print_dictionary(title, data):
 
 # Connect to ResInsight
 resinsight = rips.Instance.find()
-if resinsight is not None:
-    # Get a list of all wells
-    wells = resinsight.project.well_paths()
 
-    # Find the first case
-    cases = resinsight.project.cases()
-    c = cases[0] if len(cases) else None
+# Get a list of all wells
+wells = resinsight.project.well_paths()
 
-    for well in wells:
-        result = well.trajectory_properties(resampling_interval=10.0)
+# Find the first case
+cases = resinsight.project.cases()
+c = cases[0] if len(cases) else None
 
-        if c:
-            # Convert the result data into points
-            positions = [
-                list(coord)
-                for coord in zip(
-                    result["coordinate_x"],
-                    result["coordinate_y"],
-                    result["coordinate_z"],
-                )
-            ]
+for well in wells:
+    result = well.trajectory_properties(resampling_interval=10.0)
 
-            # Extract some properties
-            properties = [
-                (rips.PropertyType.DYNAMIC_NATIVE, "PRESSURE", 0),
-                (rips.PropertyType.STATIC_NATIVE, "FAULTDIST", 0),
-            ]
+    if c:
+        # Convert the result data into points
+        positions = [
+            list(coord)
+            for coord in zip(
+                result["coordinate_x"],
+                result["coordinate_y"],
+                result["coordinate_z"],
+            )
+        ]
 
-            for property_type, property_name, time_step in properties:
-                porosity_model = rips.PorosityModelType.MATRIX_MODEL
-                result[property_name] = c.grid_property_for_positions(
-                    positions, property_type, property_name, time_step, porosity_model
-                )
+        # Extract some properties
+        properties = [
+            (rips.PropertyType.DYNAMIC_NATIVE, "PRESSURE", 0),
+            (rips.PropertyType.STATIC_NATIVE, "FAULTDIST", 0),
+        ]
 
-            title = "Well name: " + well.name
-            print_dictionary(title, result)
+        for property_type, property_name, time_step in properties:
+            porosity_model = rips.PorosityModelType.MATRIX_MODEL
+            result[property_name] = c.grid_property_for_positions(
+                positions, property_type, property_name, time_step, porosity_model
+            )
+
+        title = "Well name: " + well.name
+        print_dictionary(title, result)

GrpcInterface/Python/rips/instance.py

@@ -116,7 +116,7 @@ class Instance:
         init_timeout: int = 300,
         command_line_parameters: List[str] = [],
         enable_heartbeat: bool = True,
-    ) -> Optional[Instance]:
+    ) -> Instance:
         """Launch a new Instance of ResInsight. This requires the environment variable
         RESINSIGHT_EXECUTABLE to be set or the parameter resinsight_executable to be provided.
         The RESINSIGHT_GRPC_PORT environment variable can be set to an alternative port number.
@@ -135,7 +135,7 @@ class Instance:
                 server periodically and aborts pending RPCs if it dies. Disable on
                 slow boxes where false positives matter (long GC pauses, debugger).
         Returns:
-            Instance: an instance object if it worked. None if not.
+            Instance: a connected instance object. Raises :class:`RipsError` on failure.
         """
 
         requested_port: int = 50051
@@ -193,29 +193,23 @@ class Instance:
 
             process = subprocess.Popen(parameters)
             pid = process.pid
-            if pid:
-                port = Instance.__read_port_number_from_file(
-                    port_number_file, init_timeout
-                )
-                if port == -1:
-                    # Need to kill the process using PID since there is no GRPC connection to use.
-                    Instance.__kill_process(pid)
-                    raise RipsError("Unable to read port number. Launch failed.")
-                else:
-                    instance = Instance(
-                        port=port,
-                        launched=True,
-                        enable_heartbeat=enable_heartbeat,
-                    )
-                    return instance
-        return None
+            port = Instance.__read_port_number_from_file(port_number_file, init_timeout)
+            if port == -1:
+                # Need to kill the process using PID since there is no GRPC connection to use.
+                Instance.__kill_process(pid)
+                raise RipsError("Unable to read port number. Launch failed.")
+            return Instance(
+                port=port,
+                launched=True,
+                enable_heartbeat=enable_heartbeat,
+            )
 
     @staticmethod
     def find(
         start_port: int = 50051,
         end_port: int = 50071,
         enable_heartbeat: bool = True,
-    ) -> Optional[Instance]:
+    ) -> Instance:
         """Search for an existing Instance of ResInsight by testing ports.
 
         By default we search from port 50051 to 50071 or if the environment