We manage our audience on multiple data extensions and I'm trying to  update them via UpdateDE on a cloudpage. One of our data extensions needs another filter besides email address and I can't seem to get the UpdateDE function to work with multiple column filters.
Sample of what current implementation looks like below,
```
%%[
SET @b = 'A'
ELSE
    Set @em = AttributeValue('emailaddr')
  IF NOT EMPTY(@email) THEN
     Set @status = UpdateDE('DE_1',1,'EmailAddress',@em,'OptIn',0)
     Set @status2 = UpdateDE('DE_2',2,'email',@em, 'b', @b, 'opt_in',0)
  ENDIF
ENDIF
]%%
```
Would appreciate any help as I'm just starting out on Ampscript.
p.s. how do people 'run' Ampscript without browsing a page? is there like a JSLint for Ampscript somewhere?

Thanks!