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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 get_token_issuer():
 """Return the issuer in which this user's token was created"""

    try:
        current_user = stack.top.current_user
        return current_user.get('iss', get_config().jwt_issuer)
    except Exception:
        pass
    return get_config().jwt_issuer