code: def test_nat_constructor():
      func = relay.Function([], z())
      test_z = relay.GlobalVar("test_z")
      test_sz = relay.GlobalVar("test_sz")
      prelude.mod[test_z] = func
      func = relay.Function([], s(z()))
      prelude.mod[test_sz] = func
      ck_mod = relay.transform.InferType()(prelude.mod)
      assert ck_mod[test_z].body.checked_type == nat()
      assert ck_mod[test_sz].body.checked_type == nat()
  
imports: import pytest
  import tvm
  from tvm import relay
  from tvm.relay import testing
  from tvm.relay.backend.interpreter import ConstructorValue
  from tvm.relay import create_executor
  from tvm.relay.prelude import Prelude, StaticTensorArrayOps
  from tvm.relay.testing import count, make_nat_value, make_nat_expr
  import numpy
label_desc: Use image node_id 8 for calling a global function with example usage: test_nat_constructor() without return types