code: function(key, value) {
        if (typeof key == "object") {
          var map = key;
          for (key in map) {
            this.__environmentChecks[key] = map[key];
          }
        } else if (value === undefined) {
          delete this.__environmentChecks[key];
        } else {
          this.__environmentChecks[key] = value;
        }
      }
docs: Sets an environment value as being checked for
  
  @param key
  @param value