code: def test_null_attribute():
      x = relay.var("x")
      y = relay.var("y")
      z = relay.Function([x], y)
      z = z.with_attr("TestAttribute", None)
      txt = astext(z)
      assert "TestAttribute=None" in txt
  
imports: import tvm
  import tvm.testing
  from tvm import te
  from tvm import relay
  from tvm.relay import testing
  import numpy
  from tvm.relay import Expr
  from tvm.relay.analysis import free_vars
  import pytest
label_desc: Use image node_id 25 for calling a global function with example usage: test_null_attribute() without return types