'Returns the value of the ``PRESERVE_CONTEXT_ON_EXCEPTION``
configuration value in case it\'s set, otherwise a sensible default
is returned.
.. versionadded:: 0.7'

@property
def preserve_context_on_exception(self):

    rv = self.config['PRESERVE_CONTEXT_ON_EXCEPTION']
    if (rv is not None):
        return rv
    return self.debug
