input: def calculate_distance(x1: int, y1: int, x2: int, y2: int) -> float:
      """ Calculate the distance between two points on a two-dimensional plane.
      >>> calculate_distance(3, 4, -9, -2)
      13.0
      >>> calculate_distance(0, 0, 0, 0)
      0.0
      """
output:     return ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5