code: def request(self, source="candidate"):
          
          node = new_ele("validate")
          if type(source) is str:
              src = util.datastore_or_url("source", source, self._assert)
          else:
              validated_element(source, ("config", qualify("config")))
              src = new_ele("source")
              src.append(source)
          node.append(src)
          return self._request(node)
docs: Validate the contents of the specified configuration.
  
          *source* is the name of the configuration datastore being validated or `config` element containing the configuration subtree to be validated
  
          :seealso: :ref:`srctarget_params`