In model UWG, the tree coverage is not read automatically

Hi all, when using ModelUWG and use the context component to select the trees , I got an error once I put uwg_is_veg_ as true. The error is in ModelUWG component and it states that the area coverage of the tree cannot be computed automatically. So I should enter the tree_cover_ input. The error is as following: "33.0 m - average height
0.46 - footprint density
1.7 - facade to site
Runtime error (MissingMemberException): ‘tuple’ object has no attribute ‘area’

Traceback:
line 391, in _autocalcualted_tree_coverage, “C:\Program Files\ladybug_tools\python\Lib\site-packages\dragonfly_uwg\properties\model.py”
line 92, in tree_coverage_fraction, “C:\Program Files\ladybug_tools\python\Lib\site-packages\dragonfly_uwg\properties\model.py”
line 81, in script"