code: function _execute(httpMethod, urlSuffix, options, errorMessage) {
          const opts = {
              headers: {
                  'Content-Type': 'application/json',
                  'ngapimockid': ngapimockid
              }
          };
  
          if (options !== undefined) {
              opts.json = options;
          }
  
          return _handleRequest(httpMethod, urlSuffix, opts, errorMessage);
      }
docs: Executes the api call with the provided information.
  @param httpMethod The http method.
  @param urlSuffix The url suffix.
  @param options The options object.
  @param errorMessage The error message.
  @return {Promise} The promise.
  @private