code: function tryToCoverWindow(code) {
  
          if (typeof window === "object") {
  
              var variables = Object.getOwnPropertyNames(window);
  
              if (!window.hasOwnProperty('window')) {
  
                  variables.push('window');
  
              }
  
              var stubDeclarations = '';
              variables.forEach(function(name) {
  
                  // If the name really can be the name of variable.
                  if (lodash.isString(name)) {
  
                      var stub = 'var ' + name + '; \n';
  
                      stubDeclarations = stubDeclarations + stub;
  
                  }
  
              });
  
              code = stubDeclarations + code;
  
          }
  
          return code;
  
      }
docs: Makes stubs of variables for avoid the changing of outside environment which has these variables too.
  
  TODO need to take this function into a separate module.
  
  @private
  @param {String} code The source code.