input: def int_to_Roman(number: int) -> str:
      """ Converts a given number into its Roman numeral form.
      >>> int_to_Roman(15)
      'XV'
      >>> int_to_Roman(9)
      'IX'
      >>> int_to_Roman(49)
      'XLIX'
      >>> int_to_Roman(1987)
      'MCMLXXXVII'
      """
output:     roman_numerals = [
          (1000, 'M'), (900, 'CM'), (500, 'D'), (400, 'CD'),
          (100, 'C'), (90, 'XC'), (50, 'L'), (40, 'XL'),
          (10, 'X'), (9, 'IX'), (5, 'V'), (4, 'IV'), (1, 'I')
      ]
      
      result = []
      for value, numeral in roman_numerals:
          while number >= value:
              result.append(numeral)
              number -= value
      
      return ''.join(result)