docs: def key_hash_algo(self, value):
          """
          A unicode string of the hash algorithm to use when creating the
          certificate identifier - "sha1" (default), or "sha256".
          """
  
          if value not in set(['sha1', 'sha256']):
              raise ValueError(_pretty_message(
                  '''
                  hash_algo must be one of "sha1", "sha256", not %s
                  ''',
                  repr(value)
              ))
  
          self._key_hash_algo = value