code: def draw_y_line(self, x, y0, y1, color="gray"):
      assert y1 > y0
      self.t.color(color)
      self.t.setheading(90)
      self.t.up()
      self.t.goto(x, y0)
      self.t.down()
      self.t.forward(y1 - y0)
  
file_path: PARL/examples/tutorials/homework/lesson2/sarsa_frozenlake/gridworld.py
imports: import gym
  import turtle
  import numpy
label_desc: Use image node_id 3 for calling the CliffWalkingWapper obj's underlying member method code with example usage: obj.draw_y_line(x, y0, y1, color) without return types