Fix legends values on histogram kernc#195

Author: zlpatel

backtesting/_plotting.py

@@ -534,9 +534,7 @@ def __eq__(self, other):
                 if is_overlay:
                     ohlc_extreme_values[source_name] = arr
                     if is_histogram:
-                        fig.vbar(x=source.data['index'], legend_label=legend_label,
-                            bottom=[0 for _ in source.data['index']], 
-                            top=arr, width=BAR_WIDTH, color=color)
+                        fig.vbar('index', BAR_WIDTH, source_name, source=source, legend_label=legend_label, color=color)
                     elif is_scatter:
                         fig.scatter(
                             'index', source_name, source=source,
@@ -550,9 +548,7 @@ def __eq__(self, other):
                             line_width=1.3)
                 else:
                     if is_histogram:
-                        r = fig.vbar(x=source.data['index'], legend_label=LegendStr(legend_label), 
-                            bottom=[0 for _ in source.data['index']], 
-                            top=arr, width=BAR_WIDTH, color=color)
+                        r = fig.vbar('index', BAR_WIDTH, source_name, source=source, legend_label=LegendStr(legend_label), color=color)
                     elif is_scatter:
                         r = fig.scatter(
                             'index', source_name, source=source,