fix python3 failure by making a relative import work
fix python3 failure by making a relative import work

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branch : trunk

inirudebwoy/pytest,oleg-alexandrov/pytest,rmfitzpatrick/pytest,hpk42/pytest,vmalloc/dessert,hunse/pytest,lukas-bednar/pytest,Bjwebb/pytest,Carreau/pytest,pfctdayelise/pytest,nicoddemus/repo-test,ericdill/pytest,Bachmann1234/pytest,ojake/pytest,The-Compiler/pytest,ionelmc/pytest,abusalimov/pytest,nicoddemus/repo-test,wfxiang08/pytest,doordash/pytest,codewarrior0/pytest,gabrielcnr/pytest,icemac/pytest,Haibo-Wang-ORG/pytest,tomviner/pytest,ghostsquad/pytest,bubenkoff/pytest,takluyver/pytest,txomon/pytest,chillbear/pytest,doordash/pytest,mbirtwell/pytest,nicoddemus/pytest,vodik/pytest,bukzor/pytest,chiller/pytest,hunse/pytest,MengJueM/pytest,codewarrior0/pytest,markshao/pytest,hackebrot/pytest,ropez/pytest,vodik/pytest,rouge8/pytest,JonathonSonesen/pytest,wfxiang08/pytest,pelme/pytest,flub/pytest,ropez/pytest,mdboom/pytest,omarkohl/pytest,Haibo-Wang-ORG/pytest,pytest-dev/pytest,malinoff/pytest,MengJueM/pytest,tomviner/pytest,pelme/pytest,userzimmermann/pytest,The-Compiler/pytest,ericdill/pytest,RonnyPfannschmidt/pytest,chiller/pytest,mdboom/pytest,bukzor/pytest,mbirtwell/pytest,bubenkoff/pytest,userzimmermann/pytest,lukas-bednar/pytest,Akasurde/pytest,chillbear/pytest,ghostsquad/pytest,tgoodlet/pytest,tareqalayan/pytest,eli-b/pytest,jaraco/pytest,hpk42/pytest,Bachmann1234/pytest,Magicjarvis/py,Bjwebb/pytest,ojake/pytest,jb098/pytest,inirudebwoy/pytest,Carreau/pytest,jb098/pytest,ionelmc/pytest,etataurov/pytest,mhils/pytest,icemac/pytest,alfredodeza/pytest,davidszotten/pytest,takluyver/pytest,ddboline/pytest,gabrielcnr/pytest,rouge8/pytest,nicoddemus/pytest,untitaker/pytest,abusalimov/pytest,untitaker/pytest,skylarjhdownes/pytest,omarkohl/pytest,mhils/pytest,MichaelAquilina/pytest,pytest-dev/py,JonathonSonesen/pytest,oleg-alexandrov/pytest