bokeh export bug

In [1]:
from bokeh.io import show, output_notebook
from bokeh.charts import Bar
import pandas as pd
In [2]:
output_notebook()
Loading BokehJS ...
In [3]:
data = pd.DataFrame({'x': [1,2,3], 'y': [12,7,8]})
show(Bar(data, label='x', values='y'))