code: def request(self, identifier, version=None, format=None):
          
          node = etree.Element(qualify("get-schema",NETCONF_MONITORING_NS))
          if identifier is not None:
              elem = etree.Element(qualify("identifier",NETCONF_MONITORING_NS))
              elem.text = identifier
              node.append(elem)
          if version is not None:
              elem = etree.Element(qualify("version",NETCONF_MONITORING_NS))
              elem.text = version
              node.append(elem)
          if format is not None:
              elem = etree.Element(qualify("format",NETCONF_MONITORING_NS))
              elem.text = format
              node.append(elem)
          return self._request(node)
docs: Retrieve a named schema, with optional revision and type.
  
          *identifier* name of the schema to be retrieved
  
          *version* version of schema to get
  
          *format* format of the schema to be retrieved, yang is the default
  
          :seealso: :ref:`filter_params`