def _add_def_paths(self, prop_dict):
    """Recursive method to add relative paths for any $ref objects.

    Args:
      prop_dict: The property dict to alter.

    Side Effects:
      Alters prop_dict in-place.
    """
    for prop_key, prop_value in prop_dict.iteritems():
      if prop_key == '$ref' and not 'prop_value'.startswith('#'):
        prop_dict[prop_key] = '#/definitions/' + prop_dict[prop_key]
      elif isinstance(prop_value, dict):
        self._add_def_paths(prop_value)
Recursive method to add relative paths for any $ref objects.

    Args:
      prop_dict: The property dict to alter.

    Side Effects:
      Alters prop_dict in-place.