prevent double refactoring when testing an installed Cython version in Py3
prevent double refactoring when testing an installed Cython version in Py3

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