es">The object should be careful about vending references to <b>self</b>; the protocol checker will convert a return value of <b>self</b> to indicate the checker rather than the object for any messages that were forwarded by the checker, but direct references to the object (bypassing the checker) could be passed around by other objects.</font></td></tr>

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<td><font face="Helvetica" size="+1"><b>Instance Variables