I propose that we should change the Python bindings so that when the virterror errors VIR_ERR_NO_DOMAIN and VIR_ERR_NO_NETWORK occur in the lookup* functions only, should cause KeyError to be raised. According to: http://docs.python.org/lib/module-exceptions.html "[KeyError is] raised when a mapping (dictionary) key is not found in the set of existing keys." I've already changed the OCaml bindings so that these errors get converted into Not_found exception, which is the "natural" exception for when something is looked up and not found. Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903