def binary_search(list, target):
    first = 0
    last = len(list) - 1
    
    while first <= last:
        midpoint = (first + last) // 2
        
        if(list[midpoint] == target):
            return midpoint
        elif(list[midpoint] < target):
            first = midpoint + 1
        else:
            last = midpoint - 1


def verify(index):
    if(index != None):
        print("Target found at index: ", index)
    else:
        print("Target not found in list")


numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

result = binary_search(numbers, 12)
verify(result)

result = binary_search(numbers, 6)
verify(result)