docs: def time(name=None):
      """
      Creates the grammar for a Time or Duration (T) field, accepting only
      numbers in a certain pattern.
  
      :param name: name for the field
      :return: grammar for the date field
      """
  
      if name is None:
          name = 'Time Field'
  
      # Basic field
      # This regex allows values from 000000 to 235959
      field = pp.Regex('(0[0-9]|1[0-9]|2[0-3])[0-5][0-9][0-5][0-9]')
  
      # Parse action
      field.setParseAction(lambda t: datetime.datetime.strptime(t[0], '%H%M%S')
                           .time())
  
      # White spaces are not removed
      field.leaveWhitespace()
  
      # Name
      field.setName(name)
  
      return field