func_code: def search(string, letter):
      test = 0
      if string[0] == letter:
          test = 1
      else:
          search(string[1:], letter)
      if test == 0:
          return False
      else:
          return True
annotation: def search(string, letter):
      if string == '':
          return False
      elif string[0] == letter:
          return True
      else:
          return search(string[1:], letter)
  