code: def localize(self):
          
          if not self._runningOnWorker():
              log.warn('The localize() method should only be invoked on a worker.')
          resource = Resource.lookup(self._resourcePath)
          if resource is None:
              return self
          else:
              def stash(tmpDirPath):
                  # Save the original dirPath such that we can restore it in globalize()
                  with open(os.path.join(tmpDirPath, '.stash'), 'w') as f:
                      f.write('1' if self.fromVirtualEnv else '0')
                      f.write(self.dirPath)
  
              resource.download(callback=stash)
              return self.__class__(dirPath=resource.localDirPath,
                                    name=self.name,
                                    fromVirtualEnv=self.fromVirtualEnv)
docs: Check if this module was saved as a resource. If it was, return a new module descriptor
          that points to a local copy of that resource. Should only be called on a worker node. On
          the leader, this method returns this resource, i.e. self.
  
          :rtype: toil.resource.Resource