Point objects have x and y attributes (X and Y in C#) attributes. Write a function calculating distance between Point a and Point b. Tests round answers to 6 decimal places.

import math

class Point:
  def __init__(self, x, y):
    self.x = x
    self.y = y

def distance(a, b):
  return math.sqrt((a.x - b.x)**2 + (a.y - b.y)**2)

test.assert_approx_equals(distance(Point(0,0), Point(0,1)), 1)
test.assert_approx_equals(distance(Point(0,0), Point(1,0)), 1)
test.assert_approx_equals(distance(Point(0,0), Point(3,4)), 5)