code: def color(self):
          
          if self.fill.type != MSO_FILL.SOLID:
              self.fill.solid()
          return self.fill.fore_color
docs: The |ColorFormat| instance that provides access to the color settings
          for this line. Essentially a shortcut for ``line.fill.fore_color``.
          As a side-effect, accessing this property causes the line fill type
          to be set to ``MSO_FILL.SOLID``. If this sounds risky for your use
          case, use ``line.fill.type`` to non-destructively discover the
          existing fill type.