code: def draw_x_line(self, y, x0, x1, color="gray"):
      assert x1 > x0
      self.t.color(color)
      self.t.setheading(0)
      self.t.up()
      self.t.goto(x0, y)
      self.t.down()
      self.t.forward(x1 - x0)
  
file_path: PARL/examples/tutorials/homework/lesson2/sarsa_frozenlake/gridworld.py
imports: import gym
  import turtle
  import numpy
label_desc: Use image node_id 2 for calling the CliffWalkingWapper obj's underlying member method code with example usage: obj.draw_x_line(y, x0, x1, color) without return types