Support for plotnine in Zeppelin - AttributeError: 'NoneType' object has no attribute 'dpi'

Fail to execute line 9: p
Traceback (most recent call last):
  File "/tmp/zeppelin_pyspark-7550126901118262154.py", line 380, in <module>
    exec(code, _zcUserQueryNameSpace)
  File "<stdin>", line 9, in <module>
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/plotnine/ggplot.py", line 95, in __repr__
    self.draw()
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/plotnine/ggplot.py", line 188, in draw
    return self._draw(return_ggplot)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/plotnine/ggplot.py", line 219, in _draw
    raise err
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/plotnine/ggplot.py", line 211, in _draw
    self._draw_legend()
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/plotnine/ggplot.py", line 481, in _draw_legend
    ax.add_artist(anchored_box)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/axes/_base.py", line 1835, in add_artist
    self._set_artist_props(a)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/axes/_base.py", line 917, in _set_artist_props
    a.set_figure(self.figure)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 154, in set_figure
    martist.Artist.set_figure(self, fig)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/artist.py", line 695, in set_figure
    self.stale = True
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/artist.py", line 230, in stale
    self.stale_callback(self, val)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/artist.py", line 51, in _stale_axes_callback
    self.axes.stale = val
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/artist.py", line 230, in stale
    self.stale_callback(self, val)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/figure.py", line 51, in _stale_figure_callback
    self.figure.stale = val
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/artist.py", line 230, in stale
    self.stale_callback(self, val)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/pyplot.py", line 589, in _auto_draw_if_interactive
    fig.canvas.draw_idle()
  File "/zeppelin/zeppelin-0.8.1-bin-all/interpreter/lib/python/backend_zinline.py", line 136, in draw_idle
    self.draw(*args, **kwargs)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/backends/backend_agg.py", line 388, in draw
    self.figure.draw(self.renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/artist.py", line 38, in draw_wrapper
    return draw(artist, renderer, *args, **kwargs)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/figure.py", line 1709, in draw
    renderer, self, artists, self.suppressComposite)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/image.py", line 135, in _draw_list_compositing_images
    a.draw(renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/artist.py", line 38, in draw_wrapper
    return draw(artist, renderer, *args, **kwargs)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/axes/_base.py", line 2647, in draw
    mimage._draw_list_compositing_images(renderer, self, artists)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/image.py", line 135, in _draw_list_compositing_images
    a.draw(renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 1169, in draw
    width, height, xdescent, ydescent = self.get_extent(renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 1071, in get_extent
    w, h, xd, yd = self.get_child().get_extent(renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 236, in get_extent
    w, h, xd, yd, offsets = self.get_extent_offsets(renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 363, in get_extent_offsets
    for c in self.get_visible_children()]
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 363, in <listcomp>
    for c in self.get_visible_children()]
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 236, in get_extent
    w, h, xd, yd, offsets = self.get_extent_offsets(renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 363, in get_extent_offsets
    for c in self.get_visible_children()]
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 363, in <listcomp>
    for c in self.get_visible_children()]
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/offsetbox.py", line 810, in get_extent
    bbox, info, d = self._text._get_layout(renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/text.py", line 276, in _get_layout
    key = self.get_prop_tup(renderer=renderer)
  File "/zeppelin/anaconda/anaconda3/envs/zeppelin/lib/python3.7/site-packages/matplotlib/text.py", line 837, in get_prop_tup
    self.figure.dpi, weakref.ref(renderer),
AttributeError: 'NoneType' object has no attribute 'dpi'