backdoor

I would be interested to know how you play a walking bass line on the "backdoor" progression: ivm7 bVII7 resolving to IMaj7 (for example in C: Fm7 Bb7 resolving to CMaj7). With 1 chord per bar, this progression is found in Lady Bird (bars 3 & 4); for 2 chord per bar, it is found in Misty (bar...