Error with folium

[Nanoseb]

When I try to run the heatmap notebook for example I get the error:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-5-d6c6ea6c7974> in <module>()
      1 corners = [(markers.loc[p].lat, markers.loc[p].lon) for p in 'ABDC']
----> 2 area_polygon = folium.features.PolygonMarker(corners, fill_opacity=0.)

AttributeError: module 'folium.features' has no attribute 'PolygonMarker'

Is there something wrong with my version of folium?