Why does “if foo:” follow the branch even if the function foo returns False?

Question

def foo(a):
    print(\"I\'m foo\")
    return False


if foo:
    print(\"OK\")
else:
    print(\"KO\")

I run it and it returns OK. I know, I should h

Answer 1

When you write

 if foo:
    print("OK")
else:
    print("KO")

you are actually testing if the function pointer foo. It is defined, so it prints "OK" and it does not call the function. With the parenthesis, you call the foo function and runs its code.