code: def validate(self, value):
          
          ref_model = self.referenceModel()
          if isinstance(value, orb.Model):
              expected_schema = ref_model.schema().name()
              received_schema = value.schema().name()
  
              if expected_schema != received_schema:
                  raise orb.errors.InvalidReference(self.name(),
                                                    expects=expected_schema,
                                                    received=received_schema)
  
          return super(ReferenceColumn, self).validate(value)
docs: Re-implements the orb.Column.validate method to verify that the
          reference model type that is used with this column instance is
          the type of value being provided.
  
          :param value: <variant>
  
          :return: <bool>