Python | My variation binary search

scratch.py

def my_binary_search(_array, item):
    n = 0  # iteration
    i = 0  # finding index
    array = _array[:]

    if item > _array[-1] or item < _array[0]:
        return None

    while len(array) != 1:
        n += 1
        mid = int(len(array) / 2)
        i += mid

        if item >= array[mid]:
            array = array[mid:]
        else:
            array = array[:mid]
            i -= mid

    return "iteration: {} position: {} value: {} target: {}".format(*[n, i, _array[i], item])