class test.support.EnvironmentVarGuard Class used to temporarily set or unset environment variables. Instances can be used as

class typing.TypeVar Type variable. Usage:

testMethodPrefix String giving the prefix of method names which will be interpreted as test methods. The default value is 'test'

testsRun The total number of tests run so far.

doctest.testsource(module, name) Convert the doctest for an object to a script. Argument module

class typing.Optional Optional type. Optional[X] is equivalent to Union[X

class typing.MutableSequence(Sequence[T]) A generic version of

@unittest.skipIf(condition, reason) Skip the decorated test if condition is true.

DocTestFailure.got The example’s actual output.

class typing.io Wrapper namespace for I/O stream types. This defines the generic type IO[AnyStr]