code: def Eq(value, message="Not equal to {!s}"):
      
      @wraps(Eq)
      def built(_value):
          if _value != value:
              raise Error(message.format(value))
          return _value
      return built
docs: Creates a validator that compares the equality of the given value to
      ``value``.
  
      A custom message can be specified with ``message``. It will be formatted
      with ``value``.