def METHOD_NAME(self, key):
    """
    Obtain the parameter of an MMTF encoded value.
    Parameters
    ----------
    key : str
        The key for the potentially encoded value.
    Returns
    -------
    codec : int or None
        The parameter of the encoded value.
        `None` if the value is not encoded.
    """
    data = self._content[key]
    if isinstance(data, bytes) and data[0] == 0:
        param = struct.unpack(">i", data[8:12])[0]
        return param
    else:
        return None