clean up a bit

pyam/figures.py

@@ -35,7 +35,7 @@ def sankey(df, mapping):
                                          right_on='variable')
     label_set = set(mapping_df_merged['source']. \
                     append(mapping_df_merged['target']))
-    label_series = pd.Series(list(label_set))
+    label_series = pd.Series(label_set)
     for ind, val in label_series.items():
         mapping_df_merged.replace(val, ind, inplace=True)
     region = get_index_levels(df, 'region')[0]
@@ -58,5 +58,5 @@ def sankey(df, mapping):
             hovertemplate='"%{source.label}" to "%{target.label}": \
                 %{value}<extra></extra>'
             ))])
-    fig.update_layout(title_text="%s_%s" %  (region, year), font_size=10)
+    fig.update_layout(title_text="%s %s" %  (region, year), font_size=10)
     return fig