code: def load_fd(self, key, noexpire=False):
          '''Look up an item in the cache and return an open file
          descriptor for the object.  It is the caller's responsibility
          to close the file descriptor.'''
  
          cachekey = self.xform_key(key)
          path = self.path(cachekey)
  
          try:
              stat = path.stat()
              if not noexpire and stat.st_mtime < time.time() - self.lifetime:
                  LOG.debug('%s has expired', key)
                  path.unlink()
                  raise KeyError(key)
  
              LOG.debug('%s found in cache', key)
              return path.open('rb')
          except OSError:
              LOG.debug('%s not found in cache', key)
              raise KeyError(keyf load_fd(self, key, noexpire=False):
          '''Look up an item in the cache and return an open file
          descriptor for the object.  It is the caller's responsibility
          to close the file descriptor.'''
  
          cachekey = self.xform_key(key)
          path = self.path(cachekey)
  
          try:
              stat = path.stat()
              if not noexpire and stat.st_mtime < time.time() - self.lifetime:
                  LOG.debug('%s has expired', key)
                  path.unlink()
                  raise KeyError(key)
  
              LOG.debug('%s found in cache', key)
              return path.open('rb')
          except OSError:
              LOG.debug('%s not found in cache', key)
              raise KeyError(key)
docs: Look up an item in the cache and return an open file
          descriptor for the object.  It is the caller's responsibility
          to close the file descriptor.