1808: facts change
1808: facts change

    == core/facts
        o sometimes it is possible that a None value gets into the facts
          dictionary; if a new fact is known for that case, the assertion
          should not fail since the value previously (being None) is as
          good as not being present and the new known value can be added.

Signed-off-by: Vinzent Steinberg <7ad6f2e9b818e1205d2345ebad99449e257d29e3@gmail.com>

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