docs: def get_all(self, sort_order=None, sort_target='key'):
          """Get all keys currently stored in etcd.
  
          :returns: sequence of (value, metadata) tuples
          """
          return self.get(
              key=_encode(b'\0'),
              metadata=True,
              sort_order=sort_order,
              sort_target=sort_target,
              range_end=_encode(b'\0'),
          )