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