Added try-except block to buffer errors from bad 'update' arguments.
Added try-except block to buffer errors from bad 'update' arguments.

(also added documentation for update)

ee-in/python-api,plotly/plotly.py,plotly/plotly.py,plotly/python-api,plotly/python-api,ee-in/python-api,ee-in/python-api,plotly/plotly.py,plotly/python-api