codility binarygap by python

binarygap.py

def solution(N):
    _gap = 0
    prev = 0
    binary_list = [int(x) for x in bin(N)[2:]]
    for idx, value in enumerate(binary_list):
        if idx == len(binary_list) - 1:
            if _gap == 0:
                return 0
            else:
                return _gap - 1
        else:
            if value == 1:
                if idx - prev > _gap:
                    _gap = idx - prev
                    prev = idx