input: Write a function to calculate the distance between two points on a two-dimensional plane. The function should take two tuples representing the coordinates of the two points and return the distance as a float. If any of the input tuples are empty, the function should return -1.
  assert distance_between_points((3, 4), (-9, -2)) == 13.0
  assert distance_between_points((0, 0), (0, 0)) == 0.0
  assert distance_between_points((1, 2), (4, 6)) == 5.0
  assert distance_between_points((), (4, 6)) == -1
  assert distance_between_points((1, 2), ()) == -1
output: def distance_between_points(point1, point2):
      if not point1 or not point2:
          return -1
      return ((point1[0] - point2[0]) ** 2 + (point1[1] - point2[1]) ** 2) ** 0.5