class _WritelnDecorator(object):
    """Used to decorate file-like objects with a handy 'writeln' method"""
    def __init__(self,stream):
        self.stream = stream
    def __getattr__(self, attr):
        if attr in ('stream', '__getstate__'):
            raise AttributeError(attr)
        return getattr(self.stream,attr)
    def writeln(self, arg=None):
        if arg:
            self.write(arg)
        self.write('\n') # text-mode streams translate to \r\n if needed