Multiple dispatch is a great way to handle branching complexity. Let's say you have Process 1 which requires Steps A, B, C and D, and Process 2, very close to Process 1, which requires Steps A, B, C' and D.

The naive implementation would be:

    def process():
        A()
        B()
        if [conditions for process 2]:
            C'()
        else:
            C()
        D()
        

You should implement it as:

    class Process1:
        def A()...
        def B()...
        def C()...
        def D()...

    class Process2(Process1):
        def C()...
            [put C'() code here]

    def process():
        right_process = figure_out_right_process()
        right_process.A()
        right_process.B()
        right_process.C()
        right_process.D()

process() becomes a lot easier to test, since you only need to mock out/outsmart figure_out_right_process() instead of mimicking the right logic for [conditions for process 2]. You can test each process independently, since you don't need to fulfil the [conditions for process 2] in each test, and if those conditions should change, you only need to change figure_out_right_process() instead of at each branch in your code.

It may look verbose with only one branch, but the second you have more than two processes, or nested branches, the class based way looks a lot cleaner.