fstring

var (
	ErrEmptyExpression       = fmt.Errorf("empty expression not allowed")
	ErrArgsNotDefined        = fmt.Errorf("args not defined")
	ErrLeftBracketNotClosed  = fmt.Errorf("single '{' is not allowed")
	ErrRightBracketNotClosed = fmt.Errorf("single '}' is not allowed")
)