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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def kinit_timeout_handle(username, realm):
 """Check if the user exists before we throw an error."""

        try:
            u = User.objects.get(username__iexact=username)
        except User.DoesNotExist:
            logger.warning("kinit timed out for {}@{} (invalid user)".format(username, realm))
            return

        logger.critical("kinit timed out for {}".format(realm), extra={
            "stack": True,
            "data": {
                "username": username
            },
            "sentry.interfaces.User": {
                "id": u.id,
                "username": username,
                "ip_address": "127.0.0.1"
            }
        })