code: func (v qrCodeVersion) formatInfo(maskPattern int) *bitset.Bitset {
  	formatID := 0
  
  	switch v.level {
  	case Low:
  		formatID = 0x08 // 0b01000
  	case Medium:
  		formatID = 0x00 // 0b00000
  	case High:
  		formatID = 0x18 // 0b11000
  	case Highest:
  		formatID = 0x10 // 0b10000
  	default:
  		log.Panicf("Invalid level %d", v.level)
  	}
  
  	if maskPattern < 0 || maskPattern > 7 {
  		log.Panicf("Invalid maskPattern %d", maskPattern)
  	}
  
  	formatID |= maskPattern & 0x7
  
  	result := bitset.New()
  
  	result.AppendUint32(formatBitSequence[formatID].regular, formatInfoLengthBits)
  
  	return result
  }
docs: // formatInfo returns the 15-bit Format Information value for a QR
  // code.