code: def _check_property(self, rest=None, require_indexed=True):
      
      if not rest:
        raise InvalidPropertyError(
            'Structured property %s requires a subproperty' % self._name)
      self._modelclass._check_properties([rest], require_indexed=require_indexed)
docs: Override for Property._check_property().
  
      Raises:
        InvalidPropertyError if no subproperty is specified or if something
        is wrong with the subproperty.