Generalise Witnessed to take any type of Witness
Generalise Witnessed to take any type of Witness

nh2/shake,ndmitchell/shake,nh2/shake,nh2/shake,ndmitchell/shake,nh2/shake,ndmitchell/shake,ndmitchell/shake,ndmitchell/shake,ndmitchell/shake,nh2/shake