code: func GetCellIDStringFromCoordsWithFixed(x, y int, xFixed, yFixed bool) string {
  	xStr := ColIndexToLetters(x)
  	if xFixed {
  		xStr = fixedCellRefChar + xStr
  	}
  	yStr := RowIndexToString(y)
  	if yFixed {
  		yStr = fixedCellRefChar + yStr
  	}
  	return xStr + yStr
  }
docs: // GetCellIDStringFromCoordsWithFixed returns the Excel format cell name that
  // represents a pair of zero based cartesian coordinates.
  // It can specify either value as fixed.