Returns a if a is truthy and then checks if b is truthy. If neither are truthy, it returns b.

Not quite. If a is not truthy, then the expression a or b will always return b.

So, there is never any reason to check the truthiness of b.

class C:
 def __repr__(self): return [k for k, v in globals().items() if v is self][0]
 def __bool__(self):
  print(f"{self}.__bool__() was called")
  return False

a, b = C(), C()
print(f"result: {a or b}")

a.__bool__() was called
result: b