code: def rgba(self, val):
          
          # Note: all other attribute sets get routed here!
          # This method is meant to do the heavy lifting of setting data
          rgba = _user_to_rgba(val, expand=False)
          if self._rgba is None:
              self._rgba = rgba  # only on init
          else:
              self._rgba[:, :rgba.shape[1]] = rgba
docs: Set the color using an Nx4 array of RGBA floats