I found out where it is. The Interface objects inherits from ParentWithBasis and the base is itself...
sage: p = Gp() sage: p._base is p True Now, setting _base to None, it gets deleted sage: p._base = None sage: del p Vincent -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
