I am trying to add a label on the top of the rectangle with an \overbrace and the letter 'q' on top of it. I am not able to achieve this. Help is appreciated. Thank you.
\usetikzlibrary {shapes.multipart, positioning}
\begin{tikzpicture}[
queue/.style={rectangle split, rectangle split horizontal,rectangle split draw splits = false,rectangle split part fill = {green!100,#1} , rectangle split parts=3, draw, anchor=center, minimum height = 0.5cm}]
\node[minimum width=4.5cm, queue = {orange!90, blue!30}, label=north: {$\overbrace{}^q$}](queue1) {\nodepart[text width=3.3cm, align=center]{one} \nodepart[text width=0.5cm, align=center]{two} $e_1$ \nodepart[text width=0.7cm, align=center]{three}$p_1$};
\end{tikzpicture}
