<xsl:choose>
<xsl:when test="starts-with(@name,$whitelist_prefix) and not($blacklist_prefix and starts-with(@name,$blacklist_prefix))">
<xsl:copy-of select="."/>
<xsl:choose>
<xsl:when test="starts-with(@name,$whitelist_prefix) and not($blacklist_prefix and starts-with(@name,$blacklist_prefix))">
<xsl:copy-of select="."/>