PYTHON 编写类，表示正n边型

>>> import math
>>> class RegularPoygon:
	def __init__(self, n=3, side=1, x=0, y=0):
		self.__n = n
		self.__side = side
		self.__x = x
		self.__y = y
	def getPerimeter(self):
		return self.__n * self.__side
	def getArea(self):
		return self.__n*pow(self.__side/2, 2)/math.tan(math.pi/self.__n)
	def distanceToPolygon(self, p):
		dx = self.__x - p.__x
		dy = self.__y - p.__y
		return math.hypot(dx, dy)

	
>>> p1 = RegularPoygon(4, 1.5)
>>> p2 = RegularPoygon(x=3, y=4)
>>> p1.getPerimeter()
6.0
>>> p1.getArea()
2.2500000000000004
>>> p2.getArea()
0.43301270189221946
>>> p1.distanceToPolygon(p2)
5.0