docs: def to_internal_value(self, data):
          """
          Dicts of native values <- Dicts of primitive datatypes.
          """
          if html.is_html_input(data):
              data = html.parse_html_dict(data)
          if not isinstance(data, dict):
              self.fail('not_a_dict', input_type=type(data).__name__)
          return {
              six.text_type(key): self.child.run_validation(value)
              for key, value in data.items()
          }