docs: def validate(self, name, data):
          """
          If there is a problem with the data, raise ValidationError.
  
          :param name: The name of this field.
          :param data: Dictionary of data for all fields.
          :raises: ValidationError
          """
          super().validate(name, data)
          if self.value is not None:
              try:
                  self.value = self.query.get(self.lookup_field == self.value)
              except (AttributeError, ValueError, peewee.DoesNotExist):
                  raise ValidationError('related', field=self.lookup_field.name, values=self.value)