code: def __call__(self, x0, rng):
      nw, nd = x0.shape
      xnew = self.get_updated_vector(rng, x0)
      if self.mode == "random":
          m = (range(nw), rng.randint(x0.shape[-1], size=nw))
      elif self.mode == "sequential":
          m = (range(nw), self.index % nd + np.zeros(nw, dtype=int))
          self.index = (self.index + 1) % nd
      else:
          return xnew, np.zeros(nw)
      x = np.array(x0)
      x[m] = xnew[m]
      return x, np.zeros(nw)
  
file_path: emcee/src/emcee/moves/gaussian.py
imports: import numpy
  from .mh import MHMove
label_desc: Use image node_id 4 for calling the _isotropic_proposal obj's underlying member method code with example usage: obj.__call__(x0, rng) and returns: x,  np, xnew,  np