code: def gettrace(self, burn=0, thin=1, chain=-1, slicing=None):
          
  
          if chain is not None:
              vlarrays = [self._vlarrays[chain]]
          else:
              vlarrays = self._vlarrays
  
          for i, vlarray in enumerate(vlarrays):
              if slicing is not None:
                  burn, stop, thin = slicing.start, slicing.stop, slicing.step
              if slicing is None or stop is None:
                  stop = len(vlarray)
              col = vlarray[burn:stop:thin]
              if i == 0:
                  data = np.asarray(col)
              else:
                  data = hstack((data, col))
  
          return data
docs: Return the trace (last by default).
  
          :Parameters:
          burn : integer
            The number of transient steps to skip.
          thin : integer
            Keep one in thin.
          chain : integer
            The index of the chain to fetch. If None, return all chains. The
            default is to return the last chain.
          slicing : slice object
            A slice overriding burn and thin assignement.