Maybe, and we can bypass it. However, sometimes it makes perfect sense to declare the variable so the return value has a concept that a reader can comprehend immediately.
current_year - birth_year
can be reasonably expected to be perceived as one’s age, but do we know that is what the programmer meant?
age = current_year - birth_year
Now there is no guess work or inference.
It won’t affect the code since the
age variable is immediately marked for garbage collection once the function is exited.