code: def filter_children(self, ctype: ContentType = None) -> List[SchemaNode]:
          
          if ctype is None:
              ctype = self.content_type()
          return [c for c in self.children if
                  not isinstance(c, (RpcActionNode, NotificationNode)) and
                  c.content_type().value & ctype.value != 0]
docs: Return receiver's children based on content type.
  
          Args:
              ctype: Content type.