input: Write a function to create a Python list comprehension that returns the squared values of a given list. The function should take a list of integers as input and return a list containing the squared values of each element.
  
  assert squared_values([1, 2, 3, 5, 8, 13]) == [1, 4, 9, 25, 64, 169]
  assert squared_values([2, 4, 6, 8]) == [4, 16, 36, 64]
  assert squared_values([]) == []
  assert squared_values([0, -1, -2, 3]) == [0, 1, 4, 9]
output: return [x**2 for x in lst]