def binary_search(search_list, value):
    low = 0
    high = len(search_list) - 1
    while low <= high:
        middle = (low + high) // 2
        if search_list[middle] > value:
            high = middle - 1
        elif search_list[middle] < value:
            low = middle + 1
        else:
            return middle
    raise ValueError("Value not found.")