input: Write a function to compare two numbers and print which one is greater.
  assert compare_numbers(10, 5) == '10 is greater than 5'
  assert compare_numbers(5, 10) == '10 is greater than 5'
  assert compare_numbers(7, 7) == '7 is greater than or equal to 7'
output: def compare_numbers(a, b):
      if a > b:
          return f'{a} is greater than {b}'
      elif b > a:
          return f'{b} is greater than {a}'
      else:
          return f'{a} is greater than or equal to {b}'