For Exercism we are using Tonel in Pharo 6.1.��

We are getting an error "Instance of TonelWriter did not understand #sourceDir:"

but the same code works fine on Pharo 7.

The 6.1 image had been updated to latest Iceberg per��https://github.com/pharo-vcs/iceberg#for-pharo-61, so I used ICeberg to updated to latest "master" of pharo-vcs/tonel but no avail.

In Pharo 7 I see TonelWriter>>sourceDir in protocol "accessing"

but if I search for "sourceDir" in the pharo-vcs/tonel repo it doesn't find it...

I'm having trouble understanding where the #sourceDir��method comes from in Pharo 7.

Which repo/branch can I load that from into another system?

cheers -ben