add and improve some more may_be_none() methods
add and improve some more may_be_none() methods

hickford/cython,dahebolangkuan/cython,encukou/cython,andreasvc/cython,dahebolangkuan/cython,marscher/cython,ABcDexter/cython,ABcDexter/cython,fperez/cython,mrGeen/cython,da-woods/cython,c-blake/cython,cython/cython,da-woods/cython,dahebolangkuan/cython,c-blake/cython,ABcDexter/cython,madjar/cython,JelleZijlstra/cython,fperez/cython,ChristopherHogan/cython,acrispin/cython,hickford/cython,roxyboy/cython,achernet/cython,madjar/cython,ABcDexter/cython,marscher/cython,acrispin/cython,scoder/cython,andreasvc/cython,achernet/cython,ChristopherHogan/cython,slonik-az/cython,c-blake/cython,slonik-az/cython,JelleZijlstra/cython,mrGeen/cython,cython/cython,slonik-az/cython,fperez/cython,scoder/cython,fabianrost84/cython,achernet/cython,hhsprings/cython,encukou/cython,cython/cython,JelleZijlstra/cython,hhsprings/cython,mcanthony/cython,hickford/cython,achernet/cython,mrGeen/cython,marscher/cython,encukou/cython,da-woods/cython,madjar/cython,mcanthony/cython,scoder/cython,da-woods/cython,c-blake/cython,madjar/cython,hhsprings/cython,hickford/cython,ABcDexter/cython,fabianrost84/cython,encukou/cython,slonik-az/cython,mcanthony/cython,acrispin/cython,ChristopherHogan/cython,encukou/cython,mcanthony/cython,andreasvc/cython,fabianrost84/cython,acrispin/cython,c-blake/cython,achernet/cython,acrispin/cython,roxyboy/cython,fperez/cython,scoder/cython,roxyboy/cython,hhsprings/cython,andreasvc/cython,dahebolangkuan/cython,hickford/cython,hhsprings/cython,roxyboy/cython,marscher/cython,dahebolangkuan/cython,madjar/cython,mrGeen/cython,roxyboy/cython,fabianrost84/cython,JelleZijlstra/cython,JelleZijlstra/cython,cython/cython,slonik-az/cython,mcanthony/cython,marscher/cython,fperez/cython,fabianrost84/cython,mrGeen/cython,andreasvc/cython