def lock_channel(self, channel, owner):
        '''
        Tag all files in channel <channel> also as channel <to_channel> 
        
        :param channel: channel to copy
        :param owner: Perform this operation on all packages of this user
        :param to_channel: Destination name (may be a channel that already exists)
        
        '''
        url = '%s/channels/%s/%s/lock' % (self.domain, owner, channel)
        res = self.session.post(url)
        self._check_response(res, [201])
Tag all files in channel <channel> also as channel <to_channel> 
        
        :param channel: channel to copy
        :param owner: Perform this operation on all packages of this user
        :param to_channel: Destination name (may be a channel that already exists)