diff --git a/yamllint/cli.py b/yamllint/cli.py
index ea0d704..0ceed35 100644
--- a/yamllint/cli.py
+++ b/yamllint/cli.py
@@ -47,7 +47,7 @@ def supports_color():
             hasattr(sys.stdout, 'isatty') and sys.stdout.isatty())
 
 
-class Format(object):
+class Format:
     @staticmethod
     def parsable(problem, filename):
         return ('%(file)s:%(line)s:%(column)s: [%(level)s] %(message)s' %
diff --git a/yamllint/linter.py b/yamllint/linter.py
index a50298a..d250598 100644
--- a/yamllint/linter.py
+++ b/yamllint/linter.py
@@ -34,7 +34,7 @@ DISABLE_RULE_PATTERN = re.compile(r'^# yamllint disable( rule:\S+)*\s*$')
 ENABLE_RULE_PATTERN = re.compile(r'^# yamllint enable( rule:\S+)*\s*$')
 
 
-class LintProblem(object):
+class LintProblem:
     """Represents a linting problem found by yamllint."""
     def __init__(self, line, column, desc='<no description>', rule=None):
         #: Line on which the problem was found (starting at 1)
diff --git a/yamllint/rules/key_ordering.py b/yamllint/rules/key_ordering.py
index ddbc24f..ad38ed7 100644
--- a/yamllint/rules/key_ordering.py
+++ b/yamllint/rules/key_ordering.py
@@ -93,7 +93,7 @@ TYPE = 'token'
 MAP, SEQ = range(2)
 
 
-class Parent(object):
+class Parent:
     def __init__(self, type):
         self.type = type
         self.keys = []