probdbn py -(continued class dbnvefilter(ve)def __init__(self,dbn)self dbn dbn self current_factors dbn init_factors self current_obs { def observe(selfobs)"""updates the current observations with obs obs is variable:value dictionary where variable is current variable ""assert all(self current_obs[var]==obs[varfor var in obs if var in self current_obs),"inconsistent current observationsself current_obs update(obsnote 'updateis dict method def query(self,var)"""returns the posterior probability of current variable var""return ve(graphicalmodel(self dbn title,self dbn vars_now,self current_factors)query(var,sel def advance(self)"""advance to the next time""prev_factors [self make_previous(facfor fac in self current_factorsprev_obs {var previous:val for var,val in self current_obs items()two_stage_factors prev_factors self dbn transition_factors self current_factors self elim_vars(two_stage_factors,self dbn vars_prev,prev_obsself current_obs { def make_previous(self,fac)"""creates new factor from fac where the current variables in fac are renamed to previous variables ""return factorrename(fac{var previous:var for var in fac variables} def elim_vars(self,factorsvarsobs)for var in varsif var in obsfactors [self project_observations(fac,obsfor fac in factorselsefactors self eliminate_var(factorsvarreturn factors example queriesversion june