code: def _posterior(self, _ID=slice(None)):
      return self.prior + self.nphi[:, _ID]
  
imports: import collections
  import functools
  import io
  import os
  import warnings
  import dgl
  import numpy
  import scipy
  import torch
label_desc: Use image node_id 2 for calling the _Dirichlet obj's underlying member method code with example usage: obj._posterior(_ID) and returns: unknown