Cannabis in Python (modified)

from math import sin,cos

class ToPolar:
    def __init__(self):
        self.x = []
        self.y = []
    def convert(self,r,phi):
        self.x.append(r*cos(phi))
        self.y.append(r*sin(phi))
    @property
    def x(self):
        return self.x
    @property
    def y(self):
        return self.y

def cannabis(phi):
    return 1+sin(phi)*(1+0.9*cos(8*phi))*(1+0.1*cos(24*phi))

class Cannabis:
    def __init__(self):
        self.tp = ToPolar()
        self.__start__()
    def __start__(self):
        phi = 0.0
        while phi < 360.0:
            y = cannabis(phi)
            self.tp.convert(y,phi)
            phi+=0.01
    def plot(self):
        '''
       plotting cannabis
       '''
        import matplotlib.pyplot as plt
        plt.plot(self.tp.x,self.tp.y,'go')
        plt.show()

x = Cannabis()
x.plot()