Dict: Removed unnecessary check for defaultdict
Dict: Removed unnecessary check for defaultdict

Checking the isinstance condition for defaultdict wasn't of any
use as defaultdict is also an instance of dict.

jerli/sympy,souravsingh/sympy,skidzo/sympy,Curious72/sympy,mafiya69/sympy,aktech/sympy,jerli/sympy,kaichogami/sympy,Arafatk/sympy,souravsingh/sympy,Arafatk/sympy,Curious72/sympy,chaffra/sympy,kaushik94/sympy,souravsingh/sympy,lindsayad/sympy,sampadsaha5/sympy,ChristinaZografou/sympy,lindsayad/sympy,hargup/sympy,oliverlee/sympy,mafiya69/sympy,lindsayad/sympy,rahuldan/sympy,skidzo/sympy,madan96/sympy,sampadsaha5/sympy,drufat/sympy,chaffra/sympy,yashsharan/sympy,madan96/sympy,rahuldan/sympy,Titan-C/sympy,sampadsaha5/sympy,kaichogami/sympy,kaushik94/sympy,oliverlee/sympy,jaimahajan1997/sympy,drufat/sympy,Arafatk/sympy,rahuldan/sympy,postvakje/sympy,jaimahajan1997/sympy,postvakje/sympy,Curious72/sympy,hargup/sympy,ChristinaZografou/sympy,kaichogami/sympy,Titan-C/sympy,drufat/sympy,aktech/sympy,jaimahajan1997/sympy,mafiya69/sympy,yashsharan/sympy,oliverlee/sympy,hargup/sympy,madan96/sympy,kaushik94/sympy,skidzo/sympy,postvakje/sympy,jerli/sympy,Titan-C/sympy,yashsharan/sympy,ChristinaZografou/sympy,chaffra/sympy,aktech/sympy