uploading a second unnamed figure using chart-studio 1.0.0a2 causes error #1622

For context, I was curious to see how the new chart_studio package would handle the switch to using the v2 rest API so I did a little QA and ran into the below issue.

I get PlotlyRequestError: Sorry, a file named 'plot from API' already exists after trying to upload a second unnamed plot to plot.ly using chart-studio 1.0.0a2.

Steps to reproduce:

import plotly.graph_objs as go
import chart_studio.plotly as py

f = go.Figure()
f.add_scatter(y=[3,4,3,5])
py.plot(f)

f.add_bar(y=[3,4,3,5])

py.plot(f)