code: func WriteFile(content string, level RecoveryLevel, size int, filename string) error {
  	var q *QRCode
  
  	q, err := New(content, level)
  
  	if err != nil {
  		return err
  	}
  
  	return q.WriteFile(size, filename)
  }
docs: // WriteFile encodes, then writes a QR Code to the given filename in PNG format.
  //
  // size is both the image width and height in pixels. If size is too small then
  // a larger image is silently written. Negative values for size cause a variable
  // sized image to be written: See the documentation for Image().