code: def test_extern():
      m = te.size_var("m")
      A = te.placeholder((m,), name="A")
  
      def extern_func(ins, outs):
          assert isinstance(ins[0], tvm.te.schedule.Buffer)
          return tvm.tir.call_packed(
              "myadd", ins[0].data, outs[0].data, m
          )
  
      B = te.extern((m,), [A], extern_func)
      assert tuple(B.shape) == (m,)
  
imports: import numpy
  import tvm
  import tvm.testing
  from tvm import te
  from tvm.topi.nn.pooling import pool2d
label_desc: Use image node_id 14 for calling a global function with example usage: test_extern() and returns: tvm