Folks, I have found a very strange bug in smach. If I call sm.execute() from a function I see the following output: Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in ignored This message is repeated several times. If I don't call execute from a function (i.e. first scope in the script) then it does not happen. I have googled the error and it looks like it is related to redefining __getattr__ . The strangest part is that this happens with code that used to ran without problems in the past. It does not happen with other state machine, only with this in particular. I don't remember having done any update to python recently. Do you have any idea why this is happening and how to solve it? Lorenzo -- Lorenzo Riano, PhD Research Associate Intelligent Systems Research Centre University of Ulster Magee campus Londonderry BT48 7JL phone: +44 (0)28 71375187 email: l.riano@ulster.ac.uk, lorenzo.riano@gmail.com skype: lorenzo.riano Webpage: http://isrc.ulster.ac.uk/Staff/LRiano/Contact.html