bare_if.py

>>> def foo(a, b, c):
...     if a:
...         return b
...     return c
...
>>> dis.dis(foo)
  2           0 LOAD_FAST                0 (a)
              3 POP_JUMP_IF_FALSE       10

  3           6 LOAD_FAST                1 (b)
              9 RETURN_VALUE

  4     >>   10 LOAD_FAST                2 (c)
             13 RETURN_VALUE


>>> def foo(a, b, c):
...     if a:
...         return b
...     else:
...         return c
...
>>> dis.dis(foo)
  2           0 LOAD_FAST                0 (a)
              3 POP_JUMP_IF_FALSE       10

  3           6 LOAD_FAST                1 (b)
              9 RETURN_VALUE

  5     >>   10 LOAD_FAST                2 (c)
             13 RETURN_VALUE
             14 LOAD_CONST               0 (None)     # Note that control will never reach here
             17 RETURN_VALUE                          # so even though there's more bytecode, it
                                                      # won't impact run-time performance