code: def plot_line(self, points: list, color='black', point_visibility=False):
          
          last_point = ()
          for point in points:
              this_point = self.plot_point(point[0], point[1],
                                           color=color, visible=point_visibility)
  
              if last_point:
                  self.canvas.create_line(last_point + this_point, fill=color)
              last_point = this_point
docs: Plot a line of points
  
          :param points: a list of tuples, each tuple containing an (x, y) point
          :param color: the color of the line
          :param point_visibility: True if the points \
          should be individually visible
          :return: None