android - Google Play 控制台去混淆崩溃

Question

我很难对 google play 控制台崩溃进行去混淆处理。该应用程序包含一个使用 proguard 的库。我希望能够消除库中发生的崩溃。我上传了mapping.txt文件，但崩溃日志看起来仍然很奇怪。它看起来如何的一些示例：

java.lang.NullPointerException: 
  at com.my.lib.MyWriter.writeTo (MyWriter.java)
  at <OR>.readFrom (MyWriter.java)
  at <OR>.readStringFrom (MyWriter.java)
  at <OR>.writeStringTo (MyWriter.java)
  at <OR>.getSize (MyWriter.java)
  at <OR>.sizeOf (MyWriter.java)
  at com.my.lib.ModelObject.getProperty (ModelObject.java)
  at <OR>.setProperty (ModelObject.java)
  at <OR>.setProperty (ModelObject.java)
  at <OR>.setProperty (ModelObject.java)
  at <OR>.writeTo (ModelObject.java)
  at <OR>.readFrom (ModelObject.java)
  at <OR>.getSize (ModelObject.java)

那些是什么<OR>意思？崩溃日志几乎列出了库中的一些对象及其方法。我应该怎么读这个？