class_docstr: For testing of AttrTree
class_docstr_tok: ["For","testing","of","AttrTree"]
code: def test_deep_delitem_str(self):
      BTree = self.tree.B
      del self.tree["B.II"]
      self.assertIsInstance(self.tree.B.II, AttrTree)
      self.assertIs(self.tree.B, BTree)
      self.assertNotIn(("B", "II"), self.tree.data)
  
imports: import pytest
  from holoviews.core.element import AttrTree
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 19 for calling the AttrTreeTest obj's underlying member method code with example usage: obj.test_deep_delitem_str() without return types