class ReleaseFrameworkError(Exception):
   def __init__(self, explanation, details=None):
      self._explanation = explanation
      self._details = details
      Exception.__init__(self, explanation)

   def _GetExplanation(self): return self.explanation
   def _GetDetails(self): return self.details

   explanation = property(_GetExplanation)
   details = property(_GetDetails)

   def __str__(self):
      return str(self.explanation)

class ReleaseFrameworkError(Exception):
   def __init__(self, explanation, details=None):
      self._explanation = explanation
      self._details = details
      Exception.__init__(self, explanation)

   def _GetExplanation(self): return self._explanation
   def _GetDetails(self): return self._details

   explanation = property(_GetExplanation)
   details = property(_GetDetails)

   def __str__(self):
      return str(self.explanation)

Fix recursive call error.