[Zope] Stupid Problem to append something to a file.. Arrgh!

Hello, I tried to append a string to a file : somefile=open(path, 'a') print >> somefile, "some string" The string is appended twice to some file. I get the same result with or without somefile.flush() or somefile.close(). When i try to open somefile in mode 'w+', i read the file with readlines and then i 'writelines' it to the file after having appended a string to it. What happens ? ho ho !! the list is entirely written a number of times equal to the number of items in the list.. I can't say that the problem may be in Zope but when i try it from a Python shell, it works well, as expected. Has everybody heard about something like that ?