input: Write a function to calculate the distance between two points.
  assert calculateDistance(0, 0, 3, 4) == 5.0
  assert calculateDistance(1, 1, 4, 5) == 5.0
  assert calculateDistance(0, 0, 0, 0) == 0.0
output: def calculateDistance(x1, y1, x2, y2):
      return ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5