code: def test_default_init(self, dist_type):
      idx = 1
      dt = dist_type(idx=idx)
  
      assert dt.idx == idx
  
imports: import copy
  import numpy
  import pandas
  import pytest
  import torch
  from causalnex.structure.pytorch.dist_type import DistTypeBinary, DistTypeCategorical, DistTypeContinuous, DistTypeOrdinal, DistTypePoisson
  from causalnex.structure.pytorch.notears import from_numpy, from_pandas
label_desc: Use image node_id 1 for calling the TestDistTypeClasses obj's underlying member method code with example usage: obj.test_default_init(dist_type) without return types