the top timeline &lt;code>sender_mc&lt;/code> should be &lt;code>this&lt;/code>.
        @param isLastRegister: &lt;strong>[optional]&lt;/strong> Indicates it's the last font registered &lt;code>true&lt;/code>, or that there are other fonts left to register &lt;code>false&lt;/code>; defaults to &lt;code>false&lt;/code>.
        @return Returns &lt;code>true&lt;/code> if parameter &lt;code>sender_mc&lt;/code> was referenced correctly and the font was successfully registered; otherwise &lt;code>false&lt;/code