input: Write a function to swap the values of two variables. The function should take two parameters, x and y, and return a tuple of the swapped values. If the input values are not provided, the function should raise a ValueError.
  assert swap_values(5, 10)==(10, 5)
  assert swap_values(1, 2)==(2, 1)
  assert swap_values(0, 0)==(0, 0)
  assert swap_values(-1, -1)==(-1, -1)
  assert swap_values()
  
  x = 5
  y = 10
  
  # Swapping process 
  x, y = swap_values(x, y)
  
  print("x:", x) 
  print("y:", y)
output: def swap_values(x=None, y=None):
      if x is None or y is None:
          raise ValueError
      return (y, x)