/home/nguyen/anaconda/lib/python2.7/site-packages/matplotlib/font_manager.py:1287: UserWarning: findfont: Font family [u'normal'] not found. Falling back to Bitstream Vera Sans
(prop.get_family(), self.defaultFamily[fontext]))
/home/nguyen/anaconda/lib/python2.7/site-packages/matplotlib/font_manager.py:1297: UserWarning: findfont: Could not match :family=Bitstream Vera Sans:style=normal:variant=normal:weight=400:stretch=normal:size=medium. Returning /usr/share/matplotlib/mpl-data/fonts/ttf/cmb10.ttf
UserWarning)
/home/nguyen/anaconda/lib/python2.7/site-packages/matplotlib/font_manager.py:1297: UserWarning: findfont: Could not match :family=Bitstream Vera Sans:style=normal:variant=normal:weight=700:stretch=normal:size=25.0. Returning /usr/share/matplotlib/mpl-data/fonts/ttf/cmb10.ttf
UserWarning)
/home/nguyen/anaconda/lib/python2.7/site-packages/matplotlib/font_manager.py:1297: UserWarning: findfont: Could not match :family=Bitstream Vera Sans:style=normal:variant=normal:weight=700:stretch=normal:size=35.0. Returning /usr/share/matplotlib/mpl-data/fonts/ttf/cmb10.ttf
UserWarning)