code: def mean_sq_jump_dist(self, discard_frac=0.1):
          
          discard = int(self.niter * discard_frac)
          return msjd(self.chain.theta[discard:])
docs: Mean squared jumping distance estimated from chain. 
  
          Parameters
          ----------
          discard_frac: float
              fraction of iterations to discard at the beginning (as a burn-in)
  
          Returns
          -------
          float