我是matplotlib的新用户,我的平台是Ubuntu10.04Python2.6.5这是我的代码importmatplotlibmatplotlib.use('Agg')importmatplotlib.pyplotaspltplt.plot([1,2,3])错误是:/usr/local/lib/python2.6/dist-packages/matplotlib/backends/__init__.py:41:UserWarning:Yourcurrentlyselectedbackend,'agg'doesnotsupportshow().PleaseselectaGUIbac