perf should return None 
perf should return None 

as it can be mistaken later for metric value, which can be also 1.
or is there another way to determine which 1 it'is False or just 1?
lets-software/shinken,KerkhoffTechnologies/shinken,lets-software/shinken,rednach/krill,savoirfairelinux/shinken,rledisez/shinken,ddurieux/alignak,savoirfairelinux/shinken,Simage/shinken,peeyush-tm/shinken,dfranco/shinken,staute/shinken_deb,tal-nino/shinken,tal-nino/shinken,naparuba/shinken,savoirfairelinux/shinken,KerkhoffTechnologies/shinken,staute/shinken_deb,tal-nino/shinken,geektophe/shinken,lets-software/shinken,h4wkmoon/shinken,rednach/krill,h4wkmoon/shinken,staute/shinken_package,staute/shinken_package,gst/alignak,h4wkmoon/shinken,gst/alignak,peeyush-tm/shinken,naparuba/shinken,rednach/krill,rednach/krill,staute/shinken_deb,rledisez/shinken,Aimage/shinken,naparuba/shinken,claneys/shinken,geektophe/shinken,staute/shinken_deb,rledisez/shinken,rledisez/shinken,titilambert/alignak,xorpaul/shinken,lets-software/shinken,titilambert/alignak,rledisez/shinken,peeyush-tm/shinken,kaji-project/shinken,titilambert/alignak,Simage/shinken,savoirfairelinux/shinken,KerkhoffTechnologies/shinken,mohierf/shinken,staute/shinken_package,ddurieux/alignak,dfranco/shinken,tal-nino/shinken,staute/shinken_package,dfranco/shinken,xorpaul/shinken,tal-nino/shinken,dfranco/shinken,KerkhoffTechnologies/shinken,geektophe/shinken,naparuba/shinken,dfranco/shinken,fpeyre/shinken,Simage/shinken,geektophe/shinken,kaji-project/shinken,claneys/shinken,KerkhoffTechnologies/shinken,Aimage/shinken,xorpaul/shinken,h4wkmoon/shinken,kaji-project/shinken,KerkhoffTechnologies/shinken,staute/shinken_deb,rednach/krill,Aimage/shinken,naparuba/shinken,Simage/shinken,h4wkmoon/shinken,fpeyre/shinken,xorpaul/shinken,fpeyre/shinken,xorpaul/shinken,peeyush-tm/shinken,savoirfairelinux/shinken,gst/alignak,ddurieux/alignak,mohierf/shinken,geektophe/shinken,h4wkmoon/shinken,claneys/shinken,kaji-project/shinken,peeyush-tm/shinken,fpeyre/shinken,rledisez/shinken,staute/shinken_package,kaji-project/shinken,Alignak-monitoring/alignak,h4wkmoon/shinken,ddurieux/alignak,staute/shinken_package,titilambert/alignak,Aimage/shinken,dfranco/shinken,ddurieux/alignak,rednach/krill,Aimage/shinken,mohierf/shinken,peeyush-tm/shinken,xorpaul/shinken,Simage/shinken,ddurieux/alignak,mohierf/shinken,fpeyre/shinken,tal-nino/shinken,kaji-project/shinken,h4wkmoon/shinken,naparuba/shinken,lets-software/shinken,xorpaul/shinken,claneys/shinken,claneys/shinken,claneys/shinken,fpeyre/shinken,gst/alignak,savoirfairelinux/shinken,Alignak-monitoring/alignak,mohierf/shinken,kaji-project/shinken,mohierf/shinken,Simage/shinken,staute/shinken_deb,lets-software/shinken,Aimage/shinken,xorpaul/shinken,geektophe/shinken