Use regex library to find matching braces

[tdegeus]

From https://stackoverflow.com/a/44019654/2646505 :

regex.search(r"[\\](My\w+)([{](?>[^{}]+|(?2))*[}])", s).group(0)

returns

\MyTitle{This is a title with some \commands{with some arguments} inside}

for

\MyTitle{This is a title with some \commands{with some arguments} inside}
which is followed by some text 
with many lines and any kind of things inside
and at some point an abstract can be defined like
\MyAbstract{%
including the abstract which can have also \commands{inside with possiblguments} or not and can longer than a line