def METHOD_NAME(ax, mean, cov, color=None, alpha=0.25,
                       factors=np.linspace(0.25, 2.0, 8)):
    """Plot error ellipse of MVN.
    Parameters
    ----------
    ax : axis
        Matplotlib axis.
    mean : array-like, shape (2,)
        Mean of the Gaussian distribution.
    cov : array-like, shape (2, 2)
        Covariance of the Gaussian distribution.
    color : str, optional (default: None)
        Color in which the ellipse should be plotted
    alpha : float, optional (default: 0.25)
        Alpha value for ellipse
    factors : array, optional (default: np.linspace(0.25, 2.0, 8))
        Multiples of the standard deviations that should be plotted.
    """
    from matplotlib.patches import Ellipse
    for factor in factors:
        angle, width, height = to_ellipse(cov, factor)
        ell = Ellipse(xy=mean, width=2.0 * width, height=2.0 * height,
                      angle=np.degrees(angle))
        ell.set_alpha(alpha)
        if color is not None:
            ell.set_color(color)
        ax.add_artist(ell)