Fix flake8 violations

sphinx/application.py

@@ -30,6 +30,7 @@ import sphinx
 from sphinx import package_dir, locale
 from sphinx.config import Config
 from sphinx.deprecation import RemovedInSphinx40Warning
+from sphinx.domains import Domain, Index
 from sphinx.environment import BuildEnvironment
 from sphinx.environment.collectors import EnvironmentCollector
 from sphinx.errors import ApplicationError, ConfigError, VersionRequirementError

sphinx/io.py

@@ -9,7 +9,7 @@
 """
 import codecs
 import warnings
-from typing import Any, List, Tuple
+from typing import Any, List
 from typing import Type  # for python3.5.1
 
 from docutils import nodes
@@ -19,7 +19,6 @@ from docutils.io import FileInput, Input, NullOutput
 from docutils.parsers import Parser
 from docutils.parsers.rst import Parser as RSTParser
 from docutils.readers import standalone
-from docutils.statemachine import StringList, string2lines
 from docutils.transforms import Transform
 from docutils.transforms.references import DanglingReferences
 from docutils.writers import UnfilteredWriter
@@ -179,7 +178,6 @@ class SphinxFileInput(FileInput):
         super().__init__(*args, **kwargs)
 
 
-
 def read_doc(app: "Sphinx", env: BuildEnvironment, filename: str) -> nodes.document:
     """Parse a document and convert to doctree."""
     # set up error_handler for the target document

sphinx/locale/__init__.py

@@ -14,8 +14,6 @@ from collections import UserString, defaultdict
 from gettext import NullTranslations
 from typing import Any, Callable, Dict, Iterable, List, Tuple, Union
 
-from sphinx.deprecation import RemovedInSphinx30Warning
-
 
 class _TranslationProxy(UserString):
     """

sphinx/registry.py

@@ -23,13 +23,11 @@ from pkg_resources import iter_entry_points
 
 from sphinx.builders import Builder
 from sphinx.config import Config
-from sphinx.deprecation import RemovedInSphinx30Warning
 from sphinx.domains import Domain, Index, ObjType
 from sphinx.domains.std import GenericObject, Target
 from sphinx.environment import BuildEnvironment
 from sphinx.errors import ExtensionError, SphinxError, VersionRequirementError
 from sphinx.extension import Extension
-from sphinx.io import SphinxFileInput
 from sphinx.locale import __
 from sphinx.parsers import Parser as SphinxParser
 from sphinx.roles import XRefRole

sphinx/versioning.py

@@ -15,7 +15,6 @@ from os import path
 from typing import Any, Dict, Iterator
 from uuid import uuid4
 
-from docutils import nodes
 from docutils.nodes import Node
 
 from sphinx.transforms import SphinxTransform