在学习绘制随机漫步图碰到的问题

各位，我遇到了这个错误能指导一下我吗？
'RandomWalk' object has no attribute 'x_values'

from random import choice
class RandoWalk():
    """一个生成随机漫步数据的类"""
    def __init__(self,num_points = 500):
        self.nun_points = num_points
        #所有随机漫步都始于（0，0）
        self.x_values = [0]
        self.y_values = [0]
    def fill_walk(self):
        while len(self.x_values) < self.num_points:
            #决定前进方向
            x_direction= choice([1, -1])
            x_distance = choice([0,1,2,3,4])
            x_step = x_direction * x_distance
            
  y_direction= choice([1, -1])
            y_distance = choice([0,1,2,3,4])
            y_step = y_direction * y_distance
            
            #拒绝原地踏步
            if x_step == 0and y_step == 0:
                continue
            #计算下一个点的x和y
            next_x = self.x_values[-1] + x_step
            next_y = self.y_values[-1] + t_step
            
            self.x_values.append(next_x)
            self.y_balues.append(next_y)
rw = RandomWalk()
rw.fill_walk()
plt.scatter(rw.x_values,rw.y_values,s = 15)
plt.show()

最后报错现实这个错误

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Input In [46], in 2>()
      1 rw = RandomWalk()
----> 2 rw.fill_walk()
      3 plt.scatter(rw.x_values,rw.y_values,s = 15)
      4 plt.show()

Input In [17], in RandomWalk.fill_walk(self)
      3 """计算随机漫步包含的所有点"""
      4 #不断漫步，直到列表达到指定长度
----> 5 while len(self.x_values) < self.num_points:
      6     #决定前进方向以及距离
      7     x_direction = choice([1,-1])
      8     x_distance = choice([0,1,2,3,4])

AttributeError: 'RandomWalk' object has no attribute 'x_values'

报错是说RandomWalk需要定义变量 x_values;

看了代码有2个主要问题，1未定义变量，2语法错误变量名引用错误，修改后可正常绘制随机漫步散点图；
如图

# 随机漫步demo
from random import choice

from matplotlib import pyplot as plt


class RandomWalk():
    """一个生成随机漫步数据的类"""
    num_points = 0
    x_values = []
    y_values = []

    def __init__(self, num_points=500):
        self.num_points = num_points
        # 所有随机漫步都始于（0，0）
        self.x_values = [0]
        self.y_values = [0]

    def fill_walk(self):
        while len(self.x_values) < self.num_points:
            # 决定前进方向
            x_direction = choice([1, -1])
            x_distance = choice([0, 1, 2, 3, 4])
            x_step = x_direction * x_distance

            y_direction = choice([1, -1])
            y_distance = choice([0, 1, 2, 3, 4])
            y_step = y_direction * y_distance

            # 拒绝原地踏步
            if x_step == 0 and y_step == 0:
                continue
            # 计算下一个点的x和y
            next_x = self.x_values[-1] + x_step
            next_y = self.y_values[-1] + y_step

            self.x_values.append(next_x)
            self.y_values.append(next_y)


rw = RandomWalk()
rw.fill_walk()
plt.scatter(rw.x_values, rw.y_values, s=15)
plt.show()