@classmethod
def GetDecoder(cls, encoding_method):
    """Retrieves the decoder object for a specific encoding method.

    Args:
      encoding_method (str): encoding method identifier.

    Returns:
      Decoder: decoder or None if the encoding method does not exists.
    """
    encoding_method = encoding_method.lower()
    decoder = cls._decoders.get(encoding_method, None)
    if not decoder:
        return None
    return decoder()
