Add more doctests to Set and Interval
Add more doctests to Set and Interval

Signed-off-by: Ondrej Certik <b816faa87b7d35274d2e545c5be11ed4376f3ccf@certik.cz>

drufat/sympy,aktech/sympy,sahmed95/sympy,souravsingh/sympy,sahmed95/sympy,pandeyadarsh/sympy,cccfran/sympy,emon10005/sympy,kaichogami/sympy,Designist/sympy,Shaswat27/sympy,debugger22/sympy,debugger22/sympy,pandeyadarsh/sympy,sahmed95/sympy,Mitchkoens/sympy,maniteja123/sympy,Titan-C/sympy,yukoba/sympy,KevinGoodsell/sympy,asm666/sympy,Gadal/sympy,yashsharan/sympy,Mitchkoens/sympy,abloomston/sympy,toolforger/sympy,jaimahajan1997/sympy,yashsharan/sympy,meghana1995/sympy,Vishluck/sympy,wyom/sympy,ChristinaZografou/sympy,abhiii5459/sympy,atsao72/sympy,yukoba/sympy,jaimahajan1997/sympy,emon10005/sympy,Curious72/sympy,farhaanbukhsh/sympy,abhiii5459/sympy,ga7g08/sympy,yukoba/sympy,atsao72/sympy,hrashk/sympy,wanglongqi/sympy,kumarkrishna/sympy,abloomston/sympy,ahhda/sympy,mattpap/sympy-polys,AkademieOlympia/sympy,mafiya69/sympy,hargup/sympy,mcdaniel67/sympy,dqnykamp/sympy,kmacinnis/sympy,cswiercz/sympy,flacjacket/sympy,sahilshekhawat/sympy,MechCoder/sympy,kumarkrishna/sympy,jamesblunt/sympy,saurabhjn76/sympy,grevutiu-gabriel/sympy,liangjiaxing/sympy,oliverlee/sympy,jerli/sympy,rahuldan/sympy,Designist/sympy,dqnykamp/sympy,MridulS/sympy,sampadsaha5/sympy,lidavidm/sympy,MechCoder/sympy,jamesblunt/sympy,Shaswat27/sympy,sunny94/temp,kumarkrishna/sympy,wanglongqi/sympy,wyom/sympy,postvakje/sympy,maniteja123/sympy,ga7g08/sympy,oliverlee/sympy,kevalds51/sympy,beni55/sympy,lidavidm/sympy,beni55/sympy,VaibhavAgarwalVA/sympy,garvitr/sympy,toolforger/sympy,aktech/sympy,vipulroxx/sympy,kaushik94/sympy,pandeyadarsh/sympy,amitjamadagni/sympy,moble/sympy,diofant/diofant,farhaanbukhsh/sympy,AkademieOlympia/sympy,madan96/sympy,madan96/sympy,maniteja123/sympy,yashsharan/sympy,kaichogami/sympy,emon10005/sympy,VaibhavAgarwalVA/sympy,bukzor/sympy,lindsayad/sympy,lindsayad/sympy,souravsingh/sympy,kaushik94/sympy,atreyv/sympy,Arafatk/sympy,atsao72/sympy,aktech/sympy,abhiii5459/sympy,pernici/sympy,dqnykamp/sympy,iamutkarshtiwari/sympy,minrk/sympy,iamutkarshtiwari/sympy,bukzor/sympy,Davidjohnwilson/sympy,toolforger/sympy,Vishluck/sympy,AunShiLord/sympy,jerli/sympy,cccfran/sympy,Sumith1896/sympy,Davidjohnwilson/sympy,hargup/sympy,Sumith1896/sympy,drufat/sympy,Curious72/sympy,shikil/sympy,sunny94/temp,hrashk/sympy,oliverlee/sympy,jbbskinny/sympy,madan96/sympy,mafiya69/sympy,garvitr/sympy,MechCoder/sympy,AunShiLord/sympy,jaimahajan1997/sympy,pbrady/sympy,farhaanbukhsh/sympy,kmacinnis/sympy,Arafatk/sympy,Arafatk/sympy,moble/sympy,meghana1995/sympy,Shaswat27/sympy,sunny94/temp,abloomston/sympy,cswiercz/sympy,VaibhavAgarwalVA/sympy,bukzor/sympy,Titan-C/sympy,kaushik94/sympy,atreyv/sympy,mcdaniel67/sympy,jbaayen/sympy,Davidjohnwilson/sympy,jamesblunt/sympy,sahilshekhawat/sympy,shipci/sympy,ChristinaZografou/sympy,saurabhjn76/sympy,kevalds51/sympy,shikil/sympy,iamutkarshtiwari/sympy,jerli/sympy,wanglongqi/sympy,kaichogami/sympy,ahhda/sympy,MridulS/sympy,drufat/sympy,minrk/sympy,asm666/sympy,Mitchkoens/sympy,hrashk/sympy,ga7g08/sympy,amitjamadagni/sympy,Vishluck/sympy,sampadsaha5/sympy,mafiya69/sympy,wyom/sympy,AkademieOlympia/sympy,rahuldan/sympy,ChristinaZografou/sympy,Designist/sympy,srjoglekar246/sympy,chaffra/sympy,kmacinnis/sympy,skidzo/sympy,lidavidm/sympy,pbrady/sympy,grevutiu-gabriel/sympy,mcdaniel67/sympy,Gadal/sympy,skidzo/sympy,Sumith1896/sympy,debugger22/sympy,sampadsaha5/sympy,Gadal/sympy,beni55/sympy,grevutiu-gabriel/sympy,jbbskinny/sympy,chaffra/sympy,vipulroxx/sympy,postvakje/sympy,skidzo/sympy,lindsayad/sympy,jbbskinny/sympy,liangjiaxing/sympy,fperez/sympy,liangjiaxing/sympy,cswiercz/sympy,hargup/sympy,shipci/sympy,rahuldan/sympy,asm666/sympy,garvitr/sympy,saurabhjn76/sympy,sahilshekhawat/sympy,pbrady/sympy,postvakje/sympy,AunShiLord/sympy,atreyv/sympy,kevalds51/sympy,cccfran/sympy,souravsingh/sympy,meghana1995/sympy,tovrstra/sympy,Titan-C/sympy,shipci/sympy,ahhda/sympy,MridulS/sympy,skirpichev/omg,shikil/sympy,Curious72/sympy,moble/sympy,vipulroxx/sympy,chaffra/sympy