code: def test_copy(self):
      avcopy = self.av.copy()
      assert avcopy[0] == self.av[0]
      assert avcopy[0] is not self.av[0]
      assert avcopy is not self.av
      avcopy[5] = {}
      assert avcopy != self.av
  
      avcopy[0]["ht"] = 4
      assert avcopy[0] != self.av[0]
      self.av[0]["ht"] = 4
      assert avcopy[0] == self.av[0]
      del self.av[0]["ht"]
  
      assert not hasattr(self.av, "__setitem__")
  
imports: import pickle
  import pytest
  import networkx
label_desc: Use image node_id 6 for calling the TestUnionAtlas obj's underlying member method code with example usage: obj.test_copy() without return types