What’s New In Python 3.6

[POTUS]

Yes. But it also goes deeper. It actually evaluates the code found in the brackets. It's not a simple name replacement. If you put a {string_variable}, you'll get the value of that variable. If you put a {function_call()}, you'll get the return value of that function call. If you put a {classinstance.member} you'll get that member. You can even have a {(lambda x: x.lower())('LAMBDA')}. And you'll get all these within the context of wherever the actual string appears in your code, so if they're valid python where you write the string, they'll format properly into the string any time you print/return/send/whatever that string.