Update app2.py

app2.py

@@ -30,17 +30,21 @@ button2 = pn.widgets.Button(icon='file-analytics', name='My papers', icon_size='
 button3 = pn.widgets.Button(icon='settings', icon_size='1.5em', name='Settings', button_type='primary', button_style='outline', width=140)
 
 # Custom RadioButtonGroup widget with additional value_change event
-class CustomRadioButtonGroup(pn.viewable.Viewable):
-    value = pn.Any(None, doc="The selected value").tag(sync=True)
-    value_change = pn.Any(None, doc="Event that is triggered when the value changes").tag(sync=True, events=True)
+class CustomRadioButtonGroup(param.Parameterized):
+    value = param.String(default="⭐", doc="The selected value")
 
-    def _process_events(self, events):
-        changed = super()._process_events(events)
-        if "value" in changed:
-            self.value_change = True
-        return changed
+    @param.depends('value', watch=True)
+    def _trigger_value_change(self):
+        self.param.trigger('value_change')
 
-select = CustomRadioButtonGroup(value="⭐", options=["⭐", "🐘"], name='String', align='center')
+select = CustomRadioButtonGroup()
+
+# Function to display the selected value
+def display_selected_value(event):
+    print(f"Selected value: {select.value}")
+
+# Attach the function to the CustomRadioButtonGroup's value_change event
+select.param.watch(display_selected_value, 'value_change')
 
 # Create a column layout for the buttons inside the toggleable sidebar
 buttons = pn.Column(