selecting a attribute from a function

Dear all,

I have written a function that returns a set. This set is of a type I made, containing multiple attributes.

create type my_type as (col1 int, col2 int)

Something likes this works:

select col1 from my_pg_func('hello');

But how can I do something like this:

select my_pg_func(table2.some_col).col1
from table2.some_col

Yours,

Aarjan