input: Write a python function to calculate the Euclidean distance between two points.
  assert calculate_distance(1, 2, 4, 6) == 5.0
  assert calculate_distance(0, 0, 3, 4) == 5.0
  assert calculate_distance(-1, -1, 2, 3) == 5.0
output: def calculate_distance(x1, y1, x2, y2):
      return ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5