def already_downloaded(filename):
cur_file = os.path.join(c.bview_dir, filename)<EOL>old_file = os.path.join(c.bview_dir, '<STR_LIT>', filename)<EOL>if not os.path.exists(cur_file) and not os.path.exists(old_file):<EOL><INDENT>return False<EOL><DEDENT>return True<EOL>
Verify that the file has not already been downloaded.