code: def exists(self, filename):
          
          result = True
          for repo in self._children:
              if not repo.exists(filename):
                  result = False
          return result
docs: Report whether a file exists on all distribution points.
  
          Determines file type by extension.
  
          Args:
              filename: Filename you wish to check. (No path! e.g.:
                  "AdobeFlashPlayer-14.0.0.176.pkg")
  
          Returns:
              Boolean