input: Write a function to generate a Python list comprehension that returns the squared values of a given list. The function should return the list comprehension directly as a string. If the input list is empty, the function should return an empty list comprehension string.
  assert get_squared_list_comprehension([1, 2, 3, 5, 8, 13])=='[x*x for x in [1, 2, 3, 5, 8, 13]]'
  assert get_squared_list_comprehension([])=='[]'
output: def get_squared_list_comprehension(lst):
      if not lst:
          return '[]'
      return f'[x*x for x in {lst}]'