sudoku

var (
	ErrFixed           = errors.New("original sudoku digits are fixed")
	ErrDupeRow         = errors.New("duplicate digit in row")
	ErrDupeCol         = errors.New("duplicate digit in column")
	ErrDupeSubReg      = errors.New("duplicate digit in subregion")
	ErrCoordOutOfRange = errors.New("row, and/or column is not between 0 and 8, inclusive")
	ErrDigitOutOfRange = errors.New("digit is not between 1 and 9, inclusive")
)