fix doctest
fix doctest

kaushik94/sympy,postvakje/sympy,mafiya69/sympy,postvakje/sympy,souravsingh/sympy,souravsingh/sympy,sampadsaha5/sympy,drufat/sympy,yashsharan/sympy,skidzo/sympy,madan96/sympy,Titan-C/sympy,skidzo/sympy,ChristinaZografou/sympy,souravsingh/sympy,Titan-C/sympy,aktech/sympy,mafiya69/sympy,rahuldan/sympy,ChristinaZografou/sympy,madan96/sympy,jaimahajan1997/sympy,kaushik94/sympy,sampadsaha5/sympy,jerli/sympy,rahuldan/sympy,Titan-C/sympy,jaimahajan1997/sympy,ChristinaZografou/sympy,chaffra/sympy,hargup/sympy,chaffra/sympy,drufat/sympy,hargup/sympy,hargup/sympy,kaushik94/sympy,madan96/sympy,aktech/sympy,jaimahajan1997/sympy,drufat/sympy,mafiya69/sympy,rahuldan/sympy,chaffra/sympy,jerli/sympy,yashsharan/sympy,yashsharan/sympy,aktech/sympy,postvakje/sympy,sampadsaha5/sympy,jerli/sympy,skidzo/sympy