def __str__(self):
	""" String representation of the circle equation,
	standard form , centre and radius """
		
        try:
	    math.sqrt(self._k)
	    #Circle raises zero degenerate case
	    assert math.sqrt(self._k) != 0,"The graph is the single point %s" % \
		   Circle.centre(self)
	    if self.__A == 0:
			
		return "\n<Equation of a circle : x%s + y%s %s %sx %s %sy %s %s = 0 \
			\n\n%s %35s %25s \n\n%s %22s %24s\n" %\
			(self._b,self._b,self._d,int(self.D),self._e, \
			int(self.E),self._f,int(self.F),
			'Standard form','Centre(x0,y0)','Radius r' \
			self._m1,Circle.centre(self),Circle.radius(self))
	    else:
		return "\n<Equation of a circle : %sx%s + %sy%s %s %sx %s %sy %s %s = 0 \
			\n\n%s %35s %25s \n\n%s %22s %24s\n" %\
			(int(self.A)self._b,int(self.A),self._b,self._d,int(self.D),self._e, \
			int(self.E),self._f,int(self.F),
			'Standard form', 'Centre(x0,y0)','Radius r' \
			self._m,Circle.centre(self),Circle.radius(self))

	#Circle raises Negative number degenerate case
        except ValueError:
		raise ValueError,\
			" r%s < 0 : Degenerate case has no graph" % self._b
 String representation of the circle equation,
	standard form , centre and radius 
recipes/Python/576531_Circle/recipe-576531.py