def linear_search(list, target):
  for i in range(0,len(list)):
    if list[i] == target:
      return i
  return None  


def verify(index):
  if index is not None:
    print("target found at index",index)
  else:
    print("target not found")

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

result =linear_search(numbers,12)
verify(result)
result =linear_search(numbers,6)
verify(result)
