code: function(key, southwest, northeast) {
          if (!(southwest instanceof AV.GeoPoint)) {
            southwest = new AV.GeoPoint(southwest);
          }
          if (!(northeast instanceof AV.GeoPoint)) {
            northeast = new AV.GeoPoint(northeast);
          }
          this._addCondition(key, '$within', { $box: [southwest, northeast] });
          return this;
        }
docs: Add a constraint to the query that requires a particular key's
  coordinates be contained within a given rectangular geographic bounding
  box.
  @param {String} key The key to be constrained.
  @param {AV.GeoPoint} southwest
  The lower-left inclusive corner of the box.
  @param {AV.GeoPoint} northeast
  The upper-right inclusive corner of the box.
  @return {AV.Query} Returns the query, so you can chain this call.