Parenthetical comprehensions (generator expressions) are equivalent to your expanded function, but list comprehensions are not. `(x for x in range(10))` creates

Parenthetical comprehensions (generator expressions) are equivalent to your expanded function, but list comprehensions are not. `(x for x in range(10))` creates a generator, but using square brackets converts it to a list, including allocating the necessary memory. If you’re trying to do yield and streaming, the parens will serve you better.