docs: function (contextModel, properties) {
                      var cacheId = this.createContextCacheId(contextModel, properties);
  
                      if (!cacheId) {
                          // empty cacheId indicates the current context
                          return this;
                      }
  
                      if (!this.$contextCache.hasOwnProperty(cacheId)) {
                          this.$contextCache[cacheId] = this.$dataSource.createContext(contextModel, properties, this);
                      }
  
                      return this.$contextCache[cacheId];
                  }