Encapsulate svg conversion

wsgi.py

@@ -173,6 +173,10 @@ def plot(
 
     plt.tight_layout()
 
+    return fig
+
+
+def convert_fig_to_svg(fig: plt.Figure) -> str:
     # Convert plot to SVG image
     imgdata = io.StringIO()
     fig.savefig(imgdata, format="svg")
@@ -228,7 +232,7 @@ def tables(
 
         df_state = df_state.sort_values("Landesbezirk")
 
-        image = plot(df_state)
+        fig = plot(df_state)
         timestamp = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
 
     except Exception as e:
@@ -245,7 +249,7 @@ def tables(
                 {"Digitale Befragung": "Int32"}
             )
 
-        image = plot()
+        fig = plot()
         timestamp = Markup(f'<font color="red">{key} 10:00:00</font>')
 
     _print_as_html(df_state)
@@ -255,7 +259,7 @@ def tables(
         "base.html",
         tables="\n".join(output_str),
         timestamp=timestamp,
-        image=image,
+        image=convert_fig_to_svg(fig),
     )