Compilation of example that should work and they don't import ipyclam net.a="AudioSource" net.a._config.hold() net.a._config.apply() Crash! hold and apply should not be available on the user API. import ipyclam net.a="AudioSource" c = net.a._config() c.hold() c.apply() clamEngine.addProcessing("unexistingType","name") RunTime error, ok but refers C++ classes clamEngine.addProcessing("type","repeatedname") RunTime error, ok but refers C++ classes clamEngine.processinType("unexistingprocessing") Crash! clamEngine.hasConnector("badprocname", ....) Crash! clamEngine.connectorPeers(