code: func (c Calendar) formatDateTimeComponentQuarter(datetime time.Time, length int) (string, error) {
  	return "", nil
  }
docs: // formatDateTimeComponentQuarter renders a calendar quarter component - this
  // is calendar quarters and not fiscal quarters.
  //  - Q1: Jan-Mar
  //  - Q2: Apr-Jun
  //  - Q3: Jul-Sep
  //  - Q4: Oct-Dec
  // TODO: not yet implemented