Added the docstrings.
Added the docstrings.

souravsingh/sympy,aktech/sympy,drufat/sympy,madan96/sympy,kaushik94/sympy,drufat/sympy,chaffra/sympy,sampadsaha5/sympy,madan96/sympy,skidzo/sympy,jaimahajan1997/sympy,skidzo/sympy,yashsharan/sympy,kaushik94/sympy,chaffra/sympy,drufat/sympy,sampadsaha5/sympy,aktech/sympy,aktech/sympy,chaffra/sympy,jaimahajan1997/sympy,sampadsaha5/sympy,postvakje/sympy,jaimahajan1997/sympy,souravsingh/sympy,madan96/sympy,postvakje/sympy,souravsingh/sympy,yashsharan/sympy,yashsharan/sympy,skidzo/sympy,postvakje/sympy,kaushik94/sympy