code: def dumps(self, obj, many=None, *args, **kwargs):
          
          serialized = self.dump(obj, many=many)
          return self.opts.render_module.dumps(serialized, *args, **kwargs)
docs: Same as :meth:`dump`, except return a JSON-encoded string.
  
          :param obj: The object to serialize.
          :param bool many: Whether to serialize `obj` as a collection. If `None`, the value
              for `self.many` is used.
          :return: A ``json`` string
          :rtype: str
  
          .. versionadded:: 1.0.0
          .. versionchanged:: 3.0.0b7
              This method returns the serialized data rather than a ``(data, errors)`` duple.
              A :exc:`ValidationError <marshmallow.exceptions.ValidationError>` is raised
              if ``obj`` is invalid.