input: Write a python function to print Roman numeral for a given number between 1 and 5.
  assert print_roman_numeral(1) == "I"
  assert print_roman_numeral(3) == "III"
  assert print_roman_numeral(5) == "V"
  assert print_roman_numeral(6) == "invalid number"
output: def print_roman_numeral(number):
      if number == 1:
          return "I"
      elif number == 2:
          return "II"
      elif number == 3:
          return "III"
      elif number == 4:
          return "IV"
      elif number == 5:
          return "V"
      else:
          return "invalid number"