input: Write a python function to search for a target value in a list and return its index.
  assert search([2, 3, 4, 5, 6], 4) == 2
  assert search([1, 2, 3, 4, 5], 6) == -1
  assert search([10, 20, 30, 40, 50], 30) == 2
output: def search(lst, target):
      try:
          return lst.index(target)
      except ValueError:
          return -1