fix session test

Author: chriddyp

plotly/tests/test_core/test_session/test_session.py

@@ -2,8 +2,7 @@
 
 from plotly.tests.utils import PlotlyTestCase
 
-from plotly.session import (update_session_plot_options, SHARING_OPTIONS,
-                            _session)
+from plotly.session import update_session_plot_options, SHARING_OPTIONS
 from plotly.exceptions import PlotlyError
 
 
@@ -22,8 +21,9 @@ def test_update_session_plot_options_valid_sharing_argument(self):
         # _session['plot_options'] should contain sharing key after
         # update_session_plot_options is called by correct arguments
         # 'public, 'private' or 'secret'
-
+        from plotly.session import _session
         for key in SHARING_OPTIONS:
             kwargs = {'sharing': key}
             update_session_plot_options(**kwargs)
+
             self.assertEqual(_session['plot_options'], kwargs)