@property
    def circumference(self):
        """The circumference of the ellipse.

        Examples
        ========

        >>> from sympy import Point, Ellipse
        >>> p1 = Point(0, 0)
        >>> e1 = Ellipse(p1, 3, 1)
        >>> e1.circumference
        12*Integral(sqrt((-8*_x**2/9 + 1)/(-_x**2 + 1)), (_x, 0, 1))

        """
        from sympy import Integral
        if self.eccentricity == 1:
            return 2*pi*self.hradius
        else:
            x = Dummy('x', real=True)
            return 4*self.major*Integral(
                sqrt((1 - (self.eccentricity*x)**2)/(x**2 - 1)), (x, 0, 1))
dataset/ETHPy150Open sympy/sympy/sympy/geometry/ellipse.py/Ellipse.circumference/swapped operands of `-`