opened_symbol option in TreeLayerControl not functioning

[Doyley1]

The opened_symbol option as part of TreeLayerControl is not functioning correctly due to a typo in treelayercontrol.py, this will mean the default '-' will always show no matter the value you put in this option.

In treelayercontrol.py in line 151:

super().__init__()
self._name = "TreeLayerControl"
kwargs["closed_symbol"] = closed_symbol
kwargs["openened_symbol"] = opened_symbol
kwargs["space_symbol"] = space_symbol
kwargs["selector_back"] = selector_back
kwargs["named_toggle"] = named_toggle
kwargs["collapse_all"] = collapse_all
kwargs["expand_all"] = expand_all
kwargs["label_is_selector"] = label_is_selector
self.options = parse_options(**kwargs)
self.base_tree = base_tree
self.overlay_tree = overlay_tree

Instead of "openened_symbol" it should be "opened_symbol"

Environment:

• folium version 0.17.0

Workaround Adjust the treelayercontrol.py file to be "opened_symbol" in the meantime

[Conengmo]

Good find! Do you want to open a PR maybe?

[Doyley1]

Yeah, I will do when I get round to it, putting it here in case anyone gets to it before me :)