Replace use of add_traces for scalar trace with add_trace

Author: Jon M. Mease

plotly/figure_factory/_bullet.py

@@ -100,7 +100,7 @@ def _bullet(df, markers, measures, ranges, subtitles, titles, orientation,
                 xaxis='x{}'.format(row + 1),
                 yaxis='y{}'.format(row + 1)
             )
-            fig.add_traces(bar)
+            fig.add_trace(bar)
 
         # measures bars
         for idx in range(len(df.iloc[row]['measures'])):
@@ -126,7 +126,7 @@ def _bullet(df, markers, measures, ranges, subtitles, titles, orientation,
                 xaxis='x{}'.format(row + 1),
                 yaxis='y{}'.format(row + 1)
             )
-            fig.add_traces(bar)
+            fig.add_trace(bar)
 
         # markers
         x = df.iloc[row]['markers'] if orientation == 'h' else [0.5]
@@ -141,7 +141,7 @@ def _bullet(df, markers, measures, ranges, subtitles, titles, orientation,
             **scatter_options
         )
 
-        fig.add_traces(markers)
+        fig.add_trace(markers)
 
         # titles and subtitles
         title = df.iloc[row]['titles']

plotly/matplotlylib/renderer.py

@@ -287,7 +287,7 @@ def draw_bar(self, coll):
                 line=go.Line(width=trace[0]['edgewidth'])))  # TODO ditto
         if len(bar['x']) > 1:
             self.msg += "    Heck yeah, I drew that bar chart\n"
-            self.plotly_fig.add_traces(bar),
+            self.plotly_fig.add_trace(bar),
             if bar_gap is not None:
                 self.plotly_fig['layout']['bargap'] = bar_gap
         else:
@@ -375,7 +375,7 @@ def draw_marked_line(self, **props):
                 marked_line['x'] = mpltools.mpl_dates_to_datestrings(
                     marked_line['x'], formatter
                 )
-            self.plotly_fig.add_traces(marked_line),
+            self.plotly_fig.add_trace(marked_line),
             self.msg += "    Heck yeah, I drew that line\n"
         else:
             self.msg += "    Line didn't have 'data' coordinates, " \