Problem with template function

[JohnAndJane]

Hi,
I want to decide how to construct the filename depending on a tag entry.

Simple code for testing the tags...

program:
if list_contains(field('tags'), ',', 'Western') then
    strcat('true ->' , field('tags'), '<-')
else
    strcat('false ->' , field('tags'), '<-')
fi

For example two books running in the template function editor gives the following values

true ->Science Fiction<-
true ->Heftserie, Western<-

But there is something wrong in my code because it returns always true.
So I tried some other code.

program:
if list_contains(field('tags'), ',', 'Western',1,0) then
    strcat('true ->' , field('tags'), '<-')
else
    strcat('false ->' , field('tags'), '<-')
fi

Same behavior, next try with

program:
_is_in = list_contains(field('tags'), ',', 'Western',1,0);

shows

1
0

for the example above. Fine, but if I try to test the variable

program:
_is_in = list_contains(field('tags'), ',', 'Western',1,0);
if _is_in = 1 then 'true' else 'false' fi

or with

program:
_is_in = list_contains(field('tags'), ',', 'Western',1,0);
if _is_in then 'true' else 'false' fi

you get

1
1

for the example above.

Seems to be on a wrong way - someone can help?

Using Calibre 7.26.0 on Win 11 Pro

[JohnAndJane]

Solved... == is better than =