我试图使用YAML转储可能有点复杂的类，并且看到以下错误。我不知道pickle做了什么，但据我所知，我没有参与任何多线程编程。运行pyunit单元测试时会发生这种情况：
知道如何找到有问题的属性吗？
ERROR: test_multi_level_needs (test_needs.needs_TestCase)
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Traceback (most recent call last):
File "/Users/rsalemi/.../test_needs.py", line 240, in test_multi_level_needs
print(yaml.dump(test2_comp))
File ".../.../yaml/__init__.py", line 200, in dump
<snipped lots of stack trace>
File ".../.../yaml/representer.py", line 91, in represent_sequence
node_item = self.represent_data(item)
File ".../.../yaml/representer.py", line 51, in represent_data
node = self.yaml_multi_representers[data_type](self, data)
File ".../.../yaml/representer.py", line 341, in represent_object
'tag:yaml.org,2002:python/object:'+function_name, state)
File ".../.../yaml/representer.py", line 116, in represent_mapping
node_value = self.represent_data(item_value)
File ".../.../yaml/representer.py", line 51, in represent_data
node = self.yaml_multi_representers[data_type](self, data)
File ".../.../yaml/representer.py", line 315, in represent_object
reduce = data.__reduce_ex__(2)
TypeError: can't pickle _thread.RLock objects