docs: def theme_color(self):
          """
          A member of :ref:`MsoThemeColorIndex` or |None| if no theme color is
          specified. When :attr:`type` is `MSO_COLOR_TYPE.THEME`, the value of
          this property will always be a member of :ref:`MsoThemeColorIndex`.
          When :attr:`type` has any other value, the value of this property is
          |None|.
  
          Assigning a member of :ref:`MsoThemeColorIndex` causes :attr:`type`
          to become `MSO_COLOR_TYPE.THEME`. Any existing RGB value is retained
          but ignored by Word. Assigning |None| causes any color specification
          to be removed such that the effective color is inherited from the
          style hierarchy.
          """
          color = self._color
          if color is None or color.themeColor is None:
              return None
          return color.themeColor