#list = [1,2,3,4]

#print(list.index(5))

def testfunction(inlist, x):
  index = -1
  for i in  range(len(inlist)):
    if inlist[i] == x:
      index = i
      break
  if index ==-1:
    errorstring = str(x)+"is not in list"
    raise ValueError(errorstring)
  return index

def main():
  list = [1,2,3,4,5]
  print(testfunction(list, 7))
  print(list.index(7))


main()