docs: def percentage(value, decimal_places=1, multiply=True, failure_string='N/A'):
      """
      Converts a floating point value into a percentage value.
      
      Number of decimal places set by the `decimal_places` kwarg. Default is one.
      
      By default the number is multiplied by 100. You can prevent it from doing
      that by setting the `multiply` keyword argument to False.
      
      If the submitted value isn't a string, returns the `failure_string` keyword
      argument.
      """
      try:
          value = float(value)
      except ValueError:
          return failure_string
      if multiply:
          value = value * 100
      return _saferound(value, decimal_places) + '%'