code: def test_plus_chain():
      with Model.define_operators({"+": lambda a, b: a}):
          m = (
              create_model(name="a")
              + create_model(name="b")
              + create_model(name="c")
              + create_model(name="d")
          )
          assert m.name == "a"
  
imports: import threading
  import time
  from collections import Counter
  import numpy
  import pytest
  from thinc.api import Adam, CupyOps, Dropout, Linear, Model, Relu, Shim, Softmax, chain, change_attr_values, concatenate, set_dropout_rate, use_ops, with_debug, wrap_model_recursive
  from thinc.compat import has_cupy_gpu
  from ..util import make_tempdir
label_desc: Use image node_id 19 for calling a global function with example usage: test_plus_chain() without return types