Codility - Binary Gap

def solution(N):
    # write your code in Python 3.6

    binary_num = bin(N)

    arr_ = []

    for i in range(2,len(binary_num)):
        if binary_num[i] == '1':
            arr_.append(i)


    arr2_ = []
    for i in range(0,len(arr_)):
        if i != len(arr_) - 1:
            tmp = arr_[i+1] - arr_[i]
            tmp = tmp - 1
            arr2_.append(tmp)

    if len(arr2_) == 0:
        return 0
    else:
        return max(arr2_)

    pass