Question

Which one is better in terms of performance:

def check():
   if (statement1 and
       statement2 and
       statement3):
     return True
   else: 
     return False

def doIt():
   if check():
     perform()

vs

def doIt():
   if (statement1 and
       statement2 and
       statement3):
      perform()

Answer 1

If (and only if) you’re having performance issues, time it yourself:

% python -m timeit -c '
statement1 = True
statement2 = True
statement3 = True

def perform():
    pass

def check():
    if (statement1 and
        statement2 and
        statement3):
        return True
    else:
        return False

def doIt():
    if check():
        perform()

doIt()
'
1000000 loops, best of 3: 1.37 usec per loop

If you’re not having performance issues, follow The Zen of Python and remember what Donald Knuth said about premature optimisation.