<include src="included_sample.html">
<if expr="True">
should be kept
</if>
in the middle...
<if expr="False">
should be removed
</if>
<if expr="False">
should be removed
<if expr="True">
should be removed because outer expr is False
</if>
should be removed
</if>
<if expr="True">
<if expr="True">
<if expr="True">
nested true should be kept
</if>
<if expr="False">
should be removed
</if>
</if>
<if expr="True">
silbing true should be kept
</if>
</if>
at the end...