update save_as to accept emf

Author: michaelbabyn

plotly/plotly/plotly.py

@@ -712,7 +712,7 @@ def get(figure_or_data, format='png', width=None, height=None, scale=None):
                           describes a plotly figure.
                           Same argument used in `py.plot`, `py.iplot`,
                           see https://plot.ly/python for examples
-        - format: 'png', 'svg', 'jpeg', 'pdf'
+        - format: 'png', 'svg', 'jpeg', 'pdf', 'emf'
         - width: output width
         - height: output height
         - scale: Increase the resolution of the image by `scale`
@@ -730,7 +730,7 @@ def get(figure_or_data, format='png', width=None, height=None, scale=None):
         # TODO: format is a built-in name... we shouldn't really use it
         figure = tools.return_figure_from_figure_or_data(figure_or_data, True)
 
-        if format not in ['png', 'svg', 'jpeg', 'pdf']:
+        if format not in ['png', 'svg', 'jpeg', 'pdf', 'emf']:
             raise exceptions.PlotlyError(
                 "Invalid format. This version of your Plotly-Python "
                 "package currently only supports png, svg, jpeg, and pdf. "
@@ -760,7 +760,8 @@ def get(figure_or_data, format='png', width=None, height=None, scale=None):
         if ('content-type' in headers and
             headers['content-type'] in ['image/png', 'image/jpeg',
                                         'application/pdf',
-                                        'image/svg+xml']):
+                                        'image/svg+xml',
+                                        'image/emf']):
             return response.content
         elif ('content-type' in headers and
               'json' in headers['content-type']):