Is the bgcolor attribute broken?

[CT83]

I am trying resize(file.path, str(width) + 'x' + str(height), fill=1, quality=40, format='jpeg', bgcolor='#40464e')
I get the error.
File "D:\MegaSync\Languages\Python\CT83-PC\venv\SmartCow-Image-Gallery\lib\site-packages\flask_resize\resizing.py", line 303, in generate data = self._generate_impl() File "D:\MegaSync\Languages\Python\CT83-PC\venv\SmartCow-Image-Gallery\lib\site-packages\flask_resize\resizing.py", line 260, in _generate_impl mat_color = ImageColor.getrgb(self.bgcolor) File "D:\MegaSync\Languages\Python\CT83-PC\venv\SmartCow-Image-Gallery\lib\site-packages\PIL\ImageColor.py", line 127, in getrgb raise ValueError("unknown color specifier: %r" % color) ValueError: unknown color specifier: '40464e'