not sure if what worked for me is a good practice, but I needed a conditional lambda, which worked this way:

• If variable A is 'Not A', I want to set variable A to 'A' and variable B to 'B'

• else (if variable A is 'A'), I want to set variable A to 'Not A' and variable B to 'Not B'

lambda: (variable_a='A', variable_b='B') if variable_a=='Not A' else (variable_a='Not A', variable_b='Not B')