input: Write a function to generate the squared values of a given list using list comprehension. The function should return the list of squared values.
  
  def squared_values(lst):
      return [x*x for x in lst]
  
  assert squared_values([1, 2, 3, 5, 8, 13])==[1, 4, 9, 25, 64, 169]
  assert squared_values([0, -1, 2, -3])==[0, 1, 4, 9]
  assert squared_values([])==[]
output: def squared_values(lst):
      return [x*x for x in lst]