When I reformat an entire document the indentation is not fixed to match my settings (i.e. 4 spaces).

For example:

class MyClass:
 def fn(self):
             if True:
                                       return False

does not change to:

class MyClass:
    def fn(self):
        if True:
            return False

Reformatting a selection should fix the indentation of any completely selected blocks.