code: def test_length():
      a = relay.TypeVar("a")
      assert prelude.mod[length].checked_type == relay.FuncType(
          [rlist(a)], relay.scalar_type("int32"), [a]
      )
      res = eval(length(cons(z(), cons(z(), cons(z(), nil())))))
      assert get_scalar(res) == 3
  
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 15 for calling a global function with example usage: test_length() without return types