small refactor on _rule to make it more efficient
small refactor on _rule to make it more efficient

gmarkall/numba,gdementen/numba,pitrou/numba,shiquanwang/numba,seibert/numba,numba/numba,stonebig/numba,sklam/numba,cpcloud/numba,stefanseefeld/numba,stefanseefeld/numba,gmarkall/numba,GaZ3ll3/numba,gmarkall/numba,shiquanwang/numba,seibert/numba,IntelLabs/numba,numba/numba,stuartarchibald/numba,stonebig/numba,GaZ3ll3/numba,numba/numba,pitrou/numba,ssarangi/numba,cpcloud/numba,pombredanne/numba,stefanseefeld/numba,pombredanne/numba,pombredanne/numba,ssarangi/numba,cpcloud/numba,pitrou/numba,gmarkall/numba,pombredanne/numba,jriehl/numba,jriehl/numba,ssarangi/numba,stuartarchibald/numba,sklam/numba,GaZ3ll3/numba,IntelLabs/numba,sklam/numba,IntelLabs/numba,sklam/numba,gdementen/numba,pombredanne/numba,stonebig/numba,gmarkall/numba,stuartarchibald/numba,sklam/numba,cpcloud/numba,IntelLabs/numba,ssarangi/numba,pitrou/numba,stuartarchibald/numba,jriehl/numba,stonebig/numba,numba/numba,shiquanwang/numba,numba/numba,stonebig/numba,pitrou/numba,GaZ3ll3/numba,seibert/numba,seibert/numba,gdementen/numba,GaZ3ll3/numba,IntelLabs/numba,stefanseefeld/numba,ssarangi/numba,stuartarchibald/numba,gdementen/numba,jriehl/numba,seibert/numba,cpcloud/numba,jriehl/numba,stefanseefeld/numba,gdementen/numba