code: def delete(self, key, cas=0):
          
          logger.debug('Deleting key %s', key)
          self._send(struct.pack(self.HEADER_STRUCT +
                                 self.COMMANDS['delete']['struct'] % len(key),
                                 self.MAGIC['request'],
                                 self.COMMANDS['delete']['command'],
                                 len(key), 0, 0, 0, len(key), 0, cas, str_to_bytes(key)))
  
          (magic, opcode, keylen, extlen, datatype, status, bodylen, opaque,
           cas, extra_content) = self._get_response()
  
          if status == self.STATUS['server_disconnected']:
              return False
          if status != self.STATUS['success'] and status not in (self.STATUS['key_not_found'], self.STATUS['key_exists']):
              raise MemcachedException('Code: %d message: %s' % (status, extra_content), status)
  
          logger.debug('Key deleted %s', key)
          return status != self.STATUS['key_exists']
docs: Delete a key/value from server. If key existed and was deleted, return True.
  
          :param key: Key's name to be deleted
          :type key: six.string_types
          :param cas: If set, only delete the key if its CAS value matches.
          :type cas: int
          :return: True in case o success and False in case of failure.
          :rtype: bool