docs: def Plural(format_str):
    """Returns whether the value should be considered a plural value.
  
    Integers greater than 1 are plural, and lists with length greater than one are
    too.
    """
    if format_str.startswith('plural?'):
      i = len('plural?')
  
      try:
        splitchar = format_str[i]  # Usually a space, but could be something else
        _, plural_val, singular_val = format_str.split(splitchar)
      except IndexError:
        raise Error('plural? must have exactly 2 arguments')
  
      def Formatter(value):
        plural = False
        if isinstance(value, int) and value > 1:
          plural = True
        if isinstance(value, list) and len(value) > 1:
          plural = True
  
        if plural:
          return plural_val
        else:
          return singular_val
  
      return Formatter
  
    else:
      return None