code: def format_field_names(obj, format_type=None):
      
      if format_type is None:
          format_type = json_api_settings.FORMAT_FIELD_NAMES
  
      if isinstance(obj, dict):
          formatted = OrderedDict()
          for key, value in obj.items():
              key = format_value(key, format_type)
              formatted[key] = value
          return formatted
  
      return obj
docs: Takes a dict and returns it with formatted keys as set in `format_type`
      or `JSON_API_FORMAT_FIELD_NAMES`
  
      :format_type: Either 'dasherize', 'camelize', 'capitalize' or 'underscore'