code: def set_capstyle(self, cs):
          
          DEBUG_MSG("set_capstyle()", 1, self)
          self.select()
          GraphicsContextBase.set_capstyle(self, cs)
          self._pen.SetCap(GraphicsContextWx._capd[self._capstyle])
          self.gfx_ctx.SetPen(self._pen)
          self.unselect()
docs: Set the capstyle as a string in ('butt', 'round', 'projecting')