 m
    // body not shown
    
}
</code>
</pre>

<p>If a transaction expects an argument that is <code>Unowned</code>, this means that the transaction cannot take ownership. 
    As a result, it is safe to pass an <code>Owned</code> reference as an argument to a transaction that expects an <code>Unowned</code> argument. 
    After the transaction returns, the caller still holds ownership.</p>

<p> 
    For example, <code>transaction bar(Money@Unowned m)</code> can accept a 
    <code>Money</code> reference w