[5/5] cache cleanup, hadle only immutable objects
[5/5] cache cleanup, hadle only immutable objects

comment out cache_it_nondummy in symbol.py

it is already not used, and we'll decide what to do with it later, when we'll
consider what to do with caching of symbols.

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