docs: def create_asset(json):
          """Create :class:`.resources.Asset` from JSON.
  
          :param json: JSON dict.
          :return: Asset instance.
          """
          result = Asset(json['sys'])
          file_dict = json['fields']['file']
          result.fields = json['fields']
          result.url = file_dict['url']
          result.mimeType = file_dict['contentType']
          return result