\documentclass{article}
\input Tcode_C.tex %The core
\input pdfcolor-rg.tex
\input Chighlighting_2.tex
\input Tcode_py.tex
\TcodeMarker{`}

\begin{document}

\TcodeSelectLanguage{C}

Code formatted as C. \ncode{unsigned _BitInt(24) a; \hfill\break const wchar_t *s=L"long string"}

\Code
int b= a/2; /* Comment */
#define macro(x) (2*(x))
a=macro(c)  //Another comment
\endCode

\TcodeSelectLanguage{py}

From here onwarsds, python is the default.

\begin{Code}
pairs = [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four')]
pairs.sort(key=lambda pair: pair[1])
pairs
\end{Code}

C code, but the default language remains python.

\begin{CCode}
int main(int argc, int **argv){
	printf(argc,__func__);
	return 0
}
\end{CCode}
% (python code continues)

\begin{Code}
pairs = [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four')]
pairs.sort(key=lambda pair: pair[1])
pairs
\end{Code}

\count20=0
\loop
  \TcodeSelectLanguage{C}
 \TcodeSelectLanguage{py}
 \advance\count20 1
\ifnum\count20<100
\repeat

\end{document}
.