How can I place a marginnote inside a description (or other list environment)

Question

I have a macro (defined with the xparse package) that creates a marginnote. It works as I would like when prepended to normal paragraph text:

\NewDocumentCommand\dates{m g}{%
   \IfNoValueTF{#2}
       {\marginnote{\scriptsize{#1}}}
       {\marginnote{\scriptsize{#2\\#1}}}}

I'd like to use it in a similar way against an item in a description environment, something like:

\begin{description}
    \item[Coding and data representation] \dates{June 2009}{September 2009} Some description
\end{description}

However the above snippet places the margin note under the label text, I would like it to appear on the far left of the page lined up with with item. I am happy to create a NewDocumentEnvironment with xparse if that would help me achieve this easier and I am open to better ways of achieving this sort of layout.

Here is a minimal example replicating the issues:

\documentclass{article}
\usepackage{xparse}
\usepackage{marginnote}
\begin{document}
\NewDocumentCommand\dates{m g}{%
  \IfNoValueTF{#2}
    {\marginnote{\scriptsize{#1}}}
    {\marginnote{\scriptsize{#2\\#1}}}}
\renewcommand*{\raggedleftmarginnote}{}
\setlength{\marginparsep}{7pt}
\reversemarginpar

\begin{description}
    \item[Coding and data representation] \dates{June 2009}{September 2009} Some description
\end{description}

\end{document}

Answer 1

Thanks to Werner's suggestion of providing a minimal working example I was able to establish that an inherited line of code:

% The offending line:
% \renewcommand*{\raggedleftmarginnote}{}

Was to blame. I'm not sure of the purpose of the asterix, but I believe this is redefining the raggedleftmarginnote command to do nothing? Perhaps someone could comment to explain why it might have been there. Without it I get the output I desired.