input: Write a function to demonstrate how to return two values from a Python function using a tuple. The function should return a string and an integer. If the input is 'XYZ', the string should be 'XYZ' and the integer should be 456. If the input is 'PQR', the string should be 'PQR' and the integer should be 789. If the input is an empty string, the function should return 'N/A' as the string and 0 as the integer.
  
  def get_multiple_values(input_str):
      if input_str == 'XYZ':
          return 'XYZ', 456
      elif input_str == 'PQR':
          return 'PQR', 789
      elif input_str == '':
          return 'N/A', 0
      else:
          return 'Unknown', -1
  
  assert get_multiple_values('XYZ') == ('XYZ', 456)
  assert get_multiple_values('PQR') == ('PQR', 789)
  assert get_multiple_values('') == ('N/A', 0)
  assert get_multiple_values('ABC') == ('Unknown', -1)
output: def get_multiple_values(input_str):
      if input_str == 'XYZ':
          return 'XYZ', 456
      elif input_str == 'PQR':
          return 'PQR', 789
      elif input_str == '':
          return 'N/A', 0
      else:
          return 'Unknown', -1