code: def structure(self, instance, client=None):
          '''Create a backend :class:`stdnet.odm.Structure` handler.
  
          :param instance: a :class:`stdnet.odm.Structure`
          :param client: Optional client handler.
          '''
          struct = self.struct_map.get(instance._meta.name)
          if struct is None:
              raise ModelNotAvailable('"%s" is not available for backend '
                                      '"%s"' % (instance._meta.name, self))
          client = client if client is not None else self.client
          return struct(instance, self, clientf structure(self, instance, client=None):
          '''Create a backend :class:`stdnet.odm.Structure` handler.
  
          :param instance: a :class:`stdnet.odm.Structure`
          :param client: Optional client handler.
          '''
          struct = self.struct_map.get(instance._meta.name)
          if struct is None:
              raise ModelNotAvailable('"%s" is not available for backend '
                                      '"%s"' % (instance._meta.name, self))
          client = client if client is not None else self.client
          return struct(instance, self, client)
docs: Create a backend :class:`stdnet.odm.Structure` handler.
  
          :param instance: a :class:`stdnet.odm.Structure`
          :param client: Optional client handler.