Remove unnecessary imports in sympy/integrals/risch.py
Remove unnecessary imports in sympy/integrals/risch.py

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