code: def instance(self, other):
      '''Returns an instance Key, by appending a name to the namespace.'''
      assert '/' not in str(other)
      return Key(str(self) + ':' + str(other)f instance(self, other):
      '''Returns an instance Key, by appending a name to the namespace.'''
      assert '/' not in str(other)
      return Key(str(self) + ':' + str(other))
docs: Returns an instance Key, by appending a name to the namespace.