docs: def error_asymptotes(pca,**kwargs):
      """
      Plots asymptotic error bounds for
      hyperbola on a stereonet.
      """
      ax = kwargs.pop("ax",current_axes())
  
      lon,lat = pca.plane_errors('upper', n=1000)
      ax.plot(lon,lat,'-')
  
      lon,lat = pca.plane_errors('lower', n=1000)
      ax.plot(lon,lat,'-')
  
      ax.plane(*pca.strike_dip())