code: function exists(modulePath, options) {
  
          if (this.aliases[modulePath]) {
              modulePath = this.aliases[modulePath];
          }
  
          var len = this.factories.length - 1; // -1 because we don't want the default factory
          for (var i = 0; this.factories && i < len; i++) {
              if (this.factories[i].isCandidate(modulePath, options)) {
                  return true;
              }
          }
  
          return false;
      }
docs: Determine if an
  @param modulePath
  @param options
  @returns {boolean}