Escape comment syntax in strings with listings

Question

Consider the following:

\documentclass{standalone}
\usepackage{listings}
\lstset{
  language=Python,
  morecomment=[s]{<<}{>>},
}

\begin{document}
\begin{lstlisting}
def expand():
    """<<expand documentation>>"""
    for hook in noweb:
        <<expand noweb hook>>
\end{lstlisting}
\end{document}

How can I get both occurrences of the syntax to be styled as the latter?

---

Edit for the wonderful Jubobs: (a less minimal working example :)

\documentclass{standalone}
\usepackage{listings}
\lstset{
  language=Python,
  showstringspaces=true,
  showspaces=false,
  showtabs=false,
  moredelim=*[s][\lst@stringstyle]{"""}{"""},
  moredelim=[s][\lst@commentstyle]{<<}{>>},
}
\renewcommand*\lstlistlistingname{List of Listings}
\lstMakeShortInline[basicstyle=\small\ttfamily]"

\begin{document}
\begin{lstlisting}
def expand():
    """foo <<expand documentation>>"""
    for hook in noweb:
        <<expand noweb hook>>

def marked_alone(node, neighbors):
    """\forall n \in N(n), "marked"(n) = 0

    There are no marked nodes in this node's neighborhood."""

    return not any(map(lambda n: n['marked'], neighbors))
\end{lstlisting}
\end{document}

with output

Answer 1

Try the following. If it suits you, I'll flesh out my answer a bit more.

\documentclass{article}

\usepackage{listings}
\makeatletter
\lstset{
  language=Python,
  moredelim=*[s][\lst@stringstyle]{"""}{"""},
  moredelim=[s][\lst@commentstyle]{<<}{>>},
  showstringspaces=false,
}
\makeatother

\begin{document}
\begin{lstlisting}
def expand():
    """foo <<expand documentation>>"""
    for hook in noweb:
        <<expand noweb hook>>
\end{lstlisting}

\end{document}