[Zope] <dtml-in> problem with defined or not defined variable as parameter

[Patrick Ulmer]

Hi,

I want to do something like that:

<dtml-if id_historie>
<dtml-in expr="dbSelect(id_historie=_.str(id_historie))">
<dtml-else>
<dtml-in expr="dbSelect(id_historie=_.str(0))">
<dtml-if>

[...]

</dtml-in>

but I get the error " unexpected end tag, for tag </dtml-in>". How can I 
query my database depending on having id_historie defined or not? Can 
somebody give me a hint?

Thanks,
Patrick