fixed the default value of sigma to "auto" instead of None
fixed the default value of sigma to "auto" instead of None

espenhgn/elephant,NeuralEnsemble/elephant,mdenker/elephant,etorre/elephant,NeuralEnsemble/elephant,JuliaSprenger/elephant,carloscanova/elephant,ccluri/elephant,dholstein/elephant,neuroelectro/elephant,neuroelectro/elephant,INM-6/elephant,NeuralEnsemble/elephant,ccluri/elephant,espenhgn/elephant,apdavison/elephant,carloscanova/elephant,apdavison/elephant,alperyeg/elephant,pietroquaglio/elephant,lzehl/elephant,etorre/elephant,Junji110/elephant,sonjagruen/elephant,alperyeg/elephant,Junji110/elephant,btel/elephant,mdenker/elephant,mdenker/elephant,btel/elephant,dholstein/elephant,sonjagruen/elephant,pietroquaglio/elephant,lzehl/elephant,INM-6/elephant,INM-6/elephant