Filter Segments Based On Empty Boolean

Your software
My Mautic version is: 2.15.3
My PHP version is: 7.1.33

Your problem
My problem is:

Lets say I have a custom Boolean which says “Phone Customer” Yes/No
i would like to filter a segment that should contain all customers that have Phone Customer = NO, or Phone Customer= EMPTY (meaning they have no value for that boolean)

I already found a solution if I want to filter only those with no value by making two conditions:
Phone Customer does not equal YES
Phone Customer does not equal NO

However now I need it to include both “NO” and No value

Setting your segment to Phone Customer does not equal YES should return both No and No Value (at least I did a test in Mautic 3.0 and it is returning both values)