Errors with expressions while using Multi-Field Formula in designer

[vucetv]

while following udemy course on alteryx designer, I am getting error when putting below in Expression using Multi-Field Formula.

errors are Unknown variables for pretty much all (ISNULL, THEN...)

The same works for the instructor though. unlike expressions in basic formula, you dont get auto fill option on formulas. 

IF ISNULL [_CurrentField_]
THEN "http://www.google.com/search?q=" + [brandname]
ELSE [_CurrentField_]
ENDIF

thanks

V

[vucetv · Accepted solution]

in trying to retype again I was successful, issue was that I didnt have parenthesis right next to ISNULL