code: def test_convert_variable():
      t1 = MyType(1)
      v1 = Variable(MyType(1), None, None)
      v2 = Variable(MyType(2), None, None)
      v3 = Variable(MyType2(0), None, None)
  
      assert t1.convert_variable(v1) is v1
      assert t1.convert_variable(v2) is None
  
      with pytest.raises(NotImplementedError):
          t1.convert_variable(v3)
  
file_path: pytensor/tests/graph/test_types.py
imports: import pytest
  from pytensor.graph.basic import Variable
  from pytensor.graph.type import Type
label_desc: Use image node_id 3 for calling a global function with example usage: test_convert_variable() without return types