生产订单提交审核提示：'NoneType' object has no attribute 'Id'，...

生产订单提交审核提示：'NoneType' object has no attribute 'Id'，是什么原因？
发生时间：09:52:52
错误来源： mscorlib
错误信息：'NoneType' object has no attribute 'Id'
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调用堆栈：
Server stack trace:
at Microsoft.Scripting.Interpreter.ThrowInstruction.Run(InterpretedFrame frame)
at Microsoft.Scripting.Interpreter.Interpreter.Run(InterpretedFrame frame)
at Microsoft.Scripting.Interpreter.LightLambda.Run3[T0,T1,T2,TRet](T0 arg0, T1 arg1, T2 arg2)
at Microsoft.Scripting.Interpreter.DynamicInstruction`3.Run(InterpretedFrame frame)
at Microsoft.Scripting.Interpreter.Interpreter.Run(InterpretedFrame frame)
at Microsoft.Scripting.Interpreter.LightLambda.Run2[T0,T1,TRet](T0 arg0, T1 arg1)
at IronPython.Compiler.PythonScriptCode.RunWorker(CodeContext ctx)
at IronPython.Compiler.PythonScriptCode.EvalWrapper(CodeContext ctx)
at IronPython.Compiler.RuntimeScriptCode.InvokeTarget(Scope scope)
at Kingdee.BOS.Scripting.PyExpressionEvaluator.Run(Expression expression, ExpressionContext context)
at