input: Write a function to calculate the distance between two points.
  assert Point(0, 0).distance(Point(3, 4)) == 5.0
  assert Point(1, 1).distance(Point(4, 5)) == 5.0
  assert Point(-1, -1).distance(Point(-4, -5)) == 5.0
output: import math
  
  class Point:
      def __init__(self, x, y):
          self.x = x
          self.y = y
  
      def distance(self, other):
          return math.sqrt((self.x - other.x) ** 2 + (self.y - other.y) ** 2)