How to do an else block for `contains` in qmake

Question

I have a qmake varaible defined in a .pro file like below.

DEFINES += SOME_VAR_STATE

I know that using contains I can check if SOME_VAR_STATE is defined or not by doing something like below.

contains(DEFINES, SOME_VAR_STATE) {
    # Do something
}

!contains(DEFINES, SOME_VAR_STATE) {
    # Do something else
}

How do I write an else case for the contains block? I don't want to write 2 blocks like done above. Instead of writing contains and !contains separately, I want to write an else block for contains. How do I do that?