import folium

print(folium.__file__)
print(folium.__version__)

lon = -(41 + 20/60. + 17/60/60.)
lat = -(20 + 59/60. + 35/60/60.)

min_lon, max_lon = -45, -35
min_lat, max_lat = -25, -15

mapa = folium.Map(location=[lat, lon], zoom_start=6,
                  min_lat=min_lat, max_lat=max_lat,
                  min_lon=min_lon, max_lon=max_lon)


kw = dict(radius=5e4, fill_color='green', fill_opacity=1)

popup = '<b>{}</b>'.format('Upper Left Corner')
c0 = folium.CircleMarker(location=[max_lat, min_lon], popup=popup, **kw)


popup = '<b>{}</b>'.format('Lower Left Corner')
c1 = folium.CircleMarker(location=[min_lat, min_lon], popup=popup, **kw)

popup = '<b>{}</b>'.format('Lower Right Corner')
c2 = folium.CircleMarker(location=[min_lat, max_lon], popup=popup, **kw)

popup = '<b>{}</b>'.format('Upper Right Corner')
c3 = folium.CircleMarker(location=[max_lat, max_lon], popup=popup, **kw)

for c in [c0, c1, c2, c3]:
    mapa.add_children(c)

mapa