input: Write a python function to create a class Point that calculates the distance from the origin.
  assert Point(3, 4).distance_from_origin() == 5.0
  assert Point(6, 8).distance_from_origin() == 10.0
  assert Point(1, 1).distance_from_origin() == 2**0.5
output: def Point:
      def __init__(self, x, y):
          self.x = x
          self.y = y
  
      def distance_from_origin(self):
          return (self.x**2 + self.y**2)**0.5