Please code in Python

def reflect_points(line: list[tuple[int, int]],
                  n: int) -> list[tuple[int, int]]:
   """
   Return the given reflected vertically across the middle horizontal
   of an n-by-n grid.

   Preconditions:
   - n > 0
   - all_within_grid(line, n)

   >>> reflect_points([(0, 1), (1, 2), (2, 3), (3, 4), (4, 5), (5, 6)], 7)
   [(6, 1), (5, 2), (4, 3), (3, 4), (2, 5), (1, 6)]
   >>> reflect_points([(0, 0), (1, 1), (2, 2), (3, 3), (4, 4), (5, 5)], 6)
   [(5, 0), (4, 1), (3, 2), (2, 3), (1, 4), (0, 5)]

"""