code: def plot_point_cov(points, nstd=2, ax=None, **kwargs):
      
      pos = points.mean(axis=0)
      cov = np.cov(points, rowvar=False)
      return plot_cov_ellipse(cov, pos, nstd, ax, **kwargs)
docs: 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