def find_flag_alias(self, flag):
        """Return alias set of a flag; return None if flag is not defined in
        "Options".
        """
        for each in self.opt_names:
            if flag in each:
                result = set(each)  # a copy
                result.remove(flag)
                return result
        return None
def find_flag_alias ( self , flag ) : for each in self . opt_names : if flag in each : result = set ( each ) result . remove ( flag ) return result return None
Return alias set of a flag; return None if flag is not defined in
        "Options".