sequences.extras: Allow from to be f in ?<slice>
sequences.extras: Allow from to be f in ?<slice>

nicolas-p/factor,AlexIljin/factor,bjourne/factor,AlexIljin/factor,mrjbq7/factor,bjourne/factor,AlexIljin/factor,AlexIljin/factor,bjourne/factor,factor/factor,mrjbq7/factor,AlexIljin/factor,mrjbq7/factor,tgunr/factor,bjourne/factor,factor/factor,factor/factor,factor/factor,tgunr/factor,nicolas-p/factor,nicolas-p/factor,bpollack/factor,bpollack/factor,bjourne/factor,bpollack/factor,nicolas-p/factor,bpollack/factor,factor/factor,bjourne/factor,mrjbq7/factor,tgunr/factor,mrjbq7/factor,tgunr/factor,factor/factor,nicolas-p/factor,AlexIljin/factor,AlexIljin/factor,bpollack/factor,nicolas-p/factor,tgunr/factor,bpollack/factor,mrjbq7/factor,tgunr/factor,bjourne/factor,nicolas-p/factor,bpollack/factor