Is it ok to skip “return None”?

Question

I wonder if it is bad manner to skip return None, when it is not needed.

Example:

def foo1(x):
    if [some condition]:
        return B         


        

Answer 1

The more I think about it, the less I think the case you describe shows good practice. It forces the client to discriminate, so client code would almost always look like:

b = foo1(123)
if b is not None:
    ...

You couldn't even write:

if b:
    ...

since, if Baz.__nonzero__ is overwritten, b could evaluate to False, even if it's not None. It would be better to have a Null-Baz instance (AKA Null Object), e.g.:

class Baz(object):
    def some_method(self):
        """some action:"""
        ...
    ...

class BazNull(Baz):
    def some_method(self):
        """nothing happens here"""
    ...

Baz.Null = BazNull()

...

def foo1(x):
    if some_condition:
        return Baz(x)
    else:
        return Baz.Null

...

b = foo1(123)
b.some_method()

The point is: help the client (who might be yourself!) to keep Cyclomatic Complexity low. The fewer branches, the better.