code: function (coordinate, options = {}, step) {
          if (!coordinate) {
              return this;
          }
          if (isFunction(options)) {
              step = options;
              options = {};
          }
          coordinate = new Coordinate(coordinate);
          if (typeof (options['animation']) === 'undefined' || options['animation']) {
              return this._panAnimation(coordinate, options['duration'], step);
          } else {
              this.setCenter(coordinate);
              return this;
          }
      }
docs: Pan to the given coordinate
  @param {Coordinate} coordinate - coordinate to pan to
  @param {Object} [options=null] - pan options
  @param {Boolean} [options.animation=null] - whether pan with animation
  @param {Boolean} [options.duration=600] - pan animation duration
  @return {Map} this