code: def delete(self, key, prev_kv=False, return_response=False):
          
          delete_request = self._build_delete_request(key, prev_kv=prev_kv)
          delete_response = self.kvstub.DeleteRange(
              delete_request,
              self.timeout,
              credentials=self.call_credentials,
              metadata=self.metadata
          )
          if return_response:
              return delete_response
          return delete_response.deleted >= 1
docs: Delete a single key in etcd.
  
          :param key: key in etcd to delete
          :param prev_kv: return the deleted key-value pair
          :type prev_kv: bool
          :param return_response: return the full response
          :type return_response: bool
          :returns: True if the key has been deleted when
                    ``return_response`` is False and a response containing
                    a header, the number of deleted keys and prev_kvs when
                    ``return_response`` is True