Define a reusable TikZ picture with \renewcommand?

Question

I have part of code which is drawing a circle. This circle i have in document many times, so i created \renewcommand and i used this three times:

\renewcommand{\DrawCircle}{
\begin{tikzpicture}[scale=1.2, every node/.style={scale=1.2}]
 \node[circle,fill=white,draw=black,thick,
       preaction={
         fill=black,opacity=.3,
         path fading=circle with fuzzy edge 20 percent,
         transform canvas={xshift=1mm,yshift=-1mm}
       }] (1) at (0,0) {};
\end{tikzpicture}
}


\DrawCircle
\DrawCircle
\DrawCircle

And I have error:

! LaTeX Error: \DrawCircle undefined.

l.80 \renewcommand{\DrawCircle} []{

But in document seems everything ok circle is 3x rendered.