use isoper instead of testing Qobj.type
use isoper instead of testing Qobj.type

zasdfgbnm/qutip,anubhavvardhan/qutip,anubhavvardhan/qutip,qutip/qutip,qutip/qutip,zasdfgbnm/qutip,cgranade/qutip,cgranade/qutip