code: def test_list_attr():
      data = mx.sym.Variable("data", attr={"mood": "angry"})
      op = mx.sym.Convolution(
          data=data,
          name="conv",
          kernel=(1, 1),
          num_filter=1,
          attr={"__mood__": "so so", "wd_mult": "x"},
      )
      assert contain(
          {"__mood__": "so so", "wd_mult": "x", "__wd_mult__": "x"},
          op.list_attr(),
      )
  
file_path: mxnet/tests/python/unittest/test_attr.py
imports: import os
  import mxnet
  from common import models
  import pickle
label_desc: Use image node_id 4 for calling a global function with example usage: test_list_attr() without return types