Instantiate AdaptiveRandomWalkMetropolis class without 'initial_state'
Remove requirement for the 'initial_state' argument when instantiating the AdaptiveRandomWalkMetropolis Class i.e. remove 'initial_state' from init()
Remove requirement for the 'initial_state' argument when instantiating the AdaptiveRandomWalkMetropolis Class i.e. remove 'initial_state' from init()