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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 RollbackAll(close=None):
 """ Rollback all transactions, according Local.conn """

    if close:
        warnings.simplefilter('default')
        warnings.warn("close parameter will not need at all.", DeprecationWarning)

    for k, v in engine_manager.items():
        session = v.session(create=False)
        if session:
            session.rollback()