Added docstring Example

Author: odovad

folium/features.py

@@ -758,6 +758,18 @@ class MarkerCluster(Layer):
         Whether the Layer will be included in LayerControls
     icon_create_function : string, default None
         Override the default behaviour, making possible to customize markers colors and sizes 
+       
+    Example
+    -------
+    >>> icon_create_function = '''
+    ... function (cluster) {
+    ...     var childCount = cluster.getChildCount();
+    ...     var c = ' marker-cluster-small';
+    ...     return new L.DivIcon({ html: '<div><span>' + childCount + '</span></div>', 
+                               className: 'marker-cluster' + c, 
+                               iconSize: new L.Point(40, 40) });
+    ...     }
+    ... '''
     """
     def __init__(self, name=None, overlay=True, control=True, icon_create_function=None):
         super(MarkerCluster, self).__init__(name=name, overlay=overlay,