def plot_point_cov(points, nstd=<NUM_LIT:2>, ax=None, **kwargs):
pos = points.mean(axis=<NUM_LIT:0>)<EOL>cov = np.cov(points, rowvar=False)<EOL>return plot_cov_ellipse(cov, pos, nstd, ax, **kwargs)<EOL>
Plots an `nstd` sigma ellipse based on the mean and covariance of a point
"cloud" (points, an Nx2 array).

Parameters
----------
    points : An Nx2 array of the data points.
    nstd : The radius of the ellipse in numbers of standard deviations.
        Defaults to 2 standard deviations.
    ax : The axis that the ellipse will be plotted on. Defaults to the
        current axis.
    Additional keyword arguments are pass on to the ellipse patch.

Returns
-------
    A matplotlib ellipse artist