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