In Python programming, pass is a null statement typically used as a placeholder. In contrast to a comment statement which is ignored by the Python interpreter, a pass statement is not ignored but nothing happens when it is executed. It results in No Operation (NOP).

Consider the case of a loop or function that we have not fully implemented yet. Without a body, the Python interpreter will complain but with a pass statement we can return to it later.

while True:
letters = ['a', 'b', 'c', 'd', 'e']
for l in letters:

pass statements are frequently used with functions and classes when you want to continue thinking at a more abstract level and later implement the code in full:

def function(args):
    pass # Remember to implement later

class EmptyClass: