builtin/utils.go:12:	anyType      = reflect.TypeOf(new(any)).Elem()
builtin/builtin.go:116:				return anyType, fmt.Errorf("invalid number of arguments (expected 1, got %d)", len(args))
builtin/builtin.go:122:			return anyType, fmt.Errorf("invalid argument for len (type %s)", args[0])
builtin/builtin.go:140:				return anyType, fmt.Errorf("invalid number of arguments (expected 1, got %d)", len(args))
builtin/builtin.go:142:			return anyType, nil
# github.com/expr-lang/expr/builtin
builtin/builtin.go:155:12: undefined: stringType
builtin/builtin.go:157:11: undefined: stringType
FAIL	github.com/expr-lang/expr [build failed]
FAIL
