def _reverseLogLevelMapping():
    """
    Reverse the above mapping, adding both the numerical keys used above and
    the corresponding string keys also used by python logging.
    @return: the reversed mapping
    """
    mapping = {}
    for logLevel, pyLogLevel in toStdlibLogLevelMapping.items():
        mapping[pyLogLevel] = logLevel
        mapping[stdlibLogging.getLevelName(pyLogLevel)] = logLevel
    return mapping

    Reverse the above mapping, adding both the numerical keys used above and
    the corresponding string keys also used by python logging.
    @return: the reversed mapping
    
stackoverflow/venv/lib/python3.6/site-packages/twisted/logger/_stdlib.py