code: def _overload_plus(operator, sleep):
      m1 = create_model(name="a")
      m2 = create_model(name="b")
      with Model.define_operators(
          {operator: lambda a, b: a.name + b.name}
      ):
          time.sleep(sleep)
          if operator == "+":
              value = m1 + m2
          else:
              value = m1 * m2
      assert value == "ab"
      assert Model._context_operators.get() == {}
  
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 21 for calling a global function with example usage: _overload_plus(operator, sleep) without return types