code: function() {
        var adds = null;
        var removes = null;
        var self = this;
        var idToPointer = function(id) {
          return { __type: 'Pointer',
                   className: self._targetClassName,
                   objectId: id };
        };
        var pointers = null;
        if (this.relationsToAdd.length > 0) {
          pointers = _.map(this.relationsToAdd, idToPointer);
          adds = { "__op": "AddRelation", "objects": pointers };
        }
  
        if (this.relationsToRemove.length > 0) {
          pointers = _.map(this.relationsToRemove, idToPointer);
          removes = { "__op": "RemoveRelation", "objects": pointers };
        }
  
        if (adds && removes) {
          return { "__op": "Batch", "ops": [adds, removes]};
        }
  
        return adds || removes || {};
      }
docs: Returns a JSON version of the operation suitable for sending to Parse.
  @return {Object}