code: def xyz2stereonet(x, y, z):
      
      x, y, z = np.atleast_1d(x, y, z)
      return cart2sph(-z, x, y)
docs: Converts x, y, z in _world_ cartesian coordinates into lower-hemisphere
      stereonet coordinates.
  
      Parameters
      ----------
      x, y, z : array-likes
          Sequences of world coordinates
  
      Returns
      -------
      lon, lat : arrays
          Sequences of longitudes and latitudes (in radians)