input: Write a function to convert integers to words using the num2words library.
  assert int_to_words(123) == 'one hundred and twenty-three'
  assert int_to_words(45) == 'forty-five'
  assert int_to_words(1001) == 'one thousand and one'
output: def int_to_words(number):
      from num2words import num2words
      return num2words(number)