class SaveAllExistingFilesCommand(sublime_plugin.ApplicationCommand):

    def run(self):
        for w in sublime.windows():
            self._save_files_in_window(w)

def _save_files_in_window(self, w):
    for v in w.views():
        self._save_exiting_file_in_view(v)

def _save_exiting_file_in_view(self, v):
    pass
sublime - save all open/loaded files that have names?