def is_reading_cfg_sufficient(setup_py):
    """
    Check the content of the setup.py file.

    If the ``setup()`` function is called with no arguments or only a
    ``cmdclass`` it is sufficient to only read the content of the ``setup.cfg``
    file.

    :param setup_py: The path of the setup.py file
    :returns: The flag if reading the setup.cfg file is sufficient
    :rtype: bool
    """
    setup_py_content = setup_py.read_text()
    # the setup function must be called with no arguments
    # or only a ``cmdclass``to be considered by this extension otherwise
    # only reading the content of the setup.cfg file isn't sufficient
    return 'setup()' in setup_py_content or \
        'setup(cmdclass=cmdclass)' in setup_py_content