*Note:* I didn't know what *.compile* was used.
*Now I do:* http://docs.python.org/library/re.html re.compile(*pattern*, *flags=0*) Compile a regular expression pattern into a regular expression object, which can be used for matching using its match()<http://docs.python.org/library/re.html#re.match>and search() <http://docs.python.org/library/re.html#re.search> methods, described below. The expression’s behaviour can be modified by specifying a *flags* value. Values can be any of the following variables, combined using bitwise OR (the | operator). The sequence prog = re.compile(pattern)result = prog.match(string) is equivalent to result = re.match(pattern, string) but using re.compile() <http://docs.python.org/library/re.html#re.compile>and saving the resulting regular expression object for reuse is more efficient when the expression will be used several times in a single program. --