Help to find a regular expression to parse po file

[gialloporpora]

Hi all,
I would like to extract string from a PO file. To do this I have created 
a little python function to parse po file and extract string:

import re
regex=re.compile("msgid (.*)\\nmsgstr (.*)\\n\\n")
m=r.findall(s)

where s is a po file like this:

msgctxt "write ubiquity commands.description"
msgid "Takes you to the Ubiquity <a 
href=\"chrome://ubiquity/content/editor.html\">command editor</a> page."
msgstr "Apre l'<a href=\"chrome://ubiquity/content/editor.html\">editor 
dei comandi</a> di Ubiquity."


#. list ubiquity commands command:
#. use | to separate multiple name values:
msgctxt "list ubiquity commands.names"
msgid "list ubiquity commands"
msgstr "elenco comandi disponibili"

msgctxt "list ubiquity commands.description"
msgid "Opens <a href=\"chrome://ubiquity/content/cmdlist.html\">the 
list</a>\n"
"      of all Ubiquity commands available and what they all do."
msgstr "Apre una <a 
href=\"chrome://ubiquity/content/cmdlist.html\">pagina</a>\n"
"      in cui sono elencati tutti i comandi disponibili e per ognuno 
viene spiegato in breve a cosa serve."



#. change ubiquity settings command:
#. use | to separate multiple name values:
msgctxt "change ubiquity settings.names"
msgid "change ubiquity settings|change ubiquity preferences|change 
ubiquity skin"
msgstr "modifica impostazioni di ubiquity|modifica preferenze di 
ubiquity|modifica tema di ubiquity"

msgctxt "change ubiquity settings.description"
msgid "Takes you to the <a 
href=\"chrome://ubiquity/content/settings.html\">settings</a> page,\n"
"      where you can change your skin, key combinations, etc."
msgstr "Apre la pagina  <a 
href=\"chrome://ubiquity/content/settings.html\">delle impostazioni</a> 
di Ubiquity,\n"
"     dalla quale è possibile modificare la combinazione da tastiera 
utilizzata per richiamare Ubiquity, il tema, ecc."



but, obviusly,  with the code above the  last string is not matched. If 
I use re.DOTALL to match also new line character it not works because it 
match the entire file, I would like to stop the matching when "msgstr" 
is found.

regex=re.compile("msgid (.*)\\nmsgstr (.*)\\n\\n\\n",re.DOTALL)

is it possible or not ?