Binary String To Number

Write from_binary(bits: str) -> int that returns the value of a string of 0s and 1s, by recursion: the empty string is worth 0; otherwise the value is the value of everything but the last character (the slice bits[:-1]) multiplied by 2, plus the last character bits[-1] converted with int(). Do NOT write a main block or any top-level test code; the tests construct the calls. Input: one line of binary digits (it may be empty), no prompt, which the tests read and pass to your function before printing the value it returns.