docstr: Test that logical negation works.
docstr_tok: ["Test","that","logical","negation","works","."]
code: def test_not(self):
      """Test that logical negation works."""
      crit = qml.BooleanFn(lambda x: x < 4)
      ncrit = ~crit
      assert crit(-2) and not ncrit(-2)
      assert not crit(10) and ncrit(10)
  
imports: import pytest
  import pennylane
label_desc: Use image node_id 2 for calling the TestBooleanFn obj's underlying member method code with example usage: obj.test_not() without return types