'Split an ISUPPORT parameter.
@type param: C{str}
@rtype: C{(str, list)}
@return C{(key, arguments)}'

@classmethod
def _splitParam(cls, param):

    if ('=' not in param):
        param += '='
    (key, value) = param.split('=', 1)
    return (key, [cls._unescapeParamValue(v) for v in value.split(',')])
