What Is "pass" in Python?

In Python, the pass statement does nothing when it's executed. It is typically used as a placeholder (for future code) in places where a statement is required syntactically (such as in loops, function and class definitions, if statements, etc.).

For example, the following function does nothing when executed; it is merely meant as a placeholder:

def foo():
  pass

print(foo()) # None

Consider the following class that has no methods yet, and is defined as a placeholder:

class Foo:
    pass

foo = Foo()
print(foo) # <__main__.Foo object at ...>

You could use pass in an if statement as well, where the code for it might not be ready yet:

n = 0

if n == 0:
    pass
else:
    print("n is not 0")

Similarly, you can use the pass statement to act as a placeholder in other places where empty code is not allowed, so that the code execution can pass without raising any errors.