pythonでテトリスを作っているのですが画面端の処理がうまくいきません

実現したいこと

Zミノにおいて画面右端での挙動が正常になるようにしたいです。

発生している問題・分からないこと

Zミノが画面右端にある時に右矢印キーを押すと意図しない正方形が出現してしまいます。これの解決方法がどうしてもわかりません。

該当のソースコード

Python
1import pygame
2pygame.init()
3from pygame.locals import *
4from pygame.mixer import *
5import sys
6import random
7import time
8SCREEN = Rect(0,0,250,415)
9
10class Tetoris(pygame.sprite.Sprite):
11    def __init__(self,tetoris,GameBoard,screen):
12        self.main_x = 5 
13        self.main_y = 1
14        self.direction = 0
15        self.object = []
16        self.update = self.start
17    
18    def start(self,GameBoard):
19        self.mino_number = random.randint(0,6)
20        self.update = self.move
21    
22    def draw(self,tetoris,GameBoard,screen):      
23        self.object = []
24        for y in range(0,4):
25            for x in range(0,4):
26                if tetoris[self.mino_number][self.direction][y][x] >0:
27                    self.object.append([self.main_y + y, self.main_x + x, tetoris[self.mino_number][self.direction][y][x]])
28        
29        b = len(self.object)
30        for i in range(0,b):
31            GameBoard[self.object[i][0]][self.object[i][1]] = self.object[i][2]
32
33        teto_color = [(0,0,0),(255,0,0),(255,224,32),(0,32,255),(96,255,128),(255,160,16),(160,32,255),(80,208,255)]
34        for y in range(0,22):
35            for x in range(0,10):
36                pygame.draw.rect(screen,teto_color[GameBoard[y][x]],(50+15*x,50+15*y,15,15))
37    
38    def move(self,GameBoard):
39        for event in pygame.event.get():
40            if event.type == KEYDOWN:
41                if event.key == pygame.K_LEFT:
42                    self.Lmove(GameBoard)
43                   
44                if event.key == pygame.K_RIGHT:
45                    self.Rmove(GameBoard)
46                if event.key == pygame.K_DOWN:
47                    self.Dmove(GameBoard)
48                if event.key == pygame.K_UP:
49                    self.Umove()
50    
51    def Lmove(self,GameBoard):
52        copy_board = GameBoard
53        spea = self.object
54        a = len(spea)
55        flag = 0
56
57        for i in range(0,a):
58            if self.main_x >0 and copy_board[spea[i][0]][spea[i][1] -1] ==0:
59                spea[i][1] -= 1
60                copy_board[spea[i][0]][spea[i][1]] = spea[i][2]
61                copy_board[spea[i][0]][spea[i][1] +1] = 0
62                flag += 1
63                
64        if flag == a:
65            flag = 0
66            self.main_x -= 1
67            spea = []
68            copy_board = []
69    
70    def Rmove(self,GameBoard):
71        copy_board = GameBoard
72        spea = self.object
73        a = len(spea)
74        flag = 0
75       
76        for i in range(a-1,-1,-1):
77                
78            if spea[i][1] < 9 and copy_board[spea[i][0]][spea[i][1] + 1] == 0:
79                spea[i][1] += 1
80                copy_board[spea[i][0]][spea[i][1]] = spea[i][2]
81                copy_board[spea[i][0]][spea[i][1] -1] = 0
82                flag += 1           
83        if flag == a:
84            flag = 0
85            self.main_x += 1
86            spea = []
87            copy_board = []
88    
89    def Dmove(self,GameBoard):
90        copy_board = GameBoard
91        spea = self.object
92        a = len(spea)
93        flag = 0
94
95        for i in range(a-1,-1,-1):
96            if spea[i][0] <21 and copy_board[spea[i][0]+1][spea[i][1] ] ==0:
97                spea[i][0] += 1
98                copy_board[spea[i][0]][spea[i][1]] = spea[i][2]
99                copy_board[spea[i][0]-1][spea[i][1]] = 0
100                flag += 1
101                
102        if flag == a:
103            flag = 0
104            self.main_y += 1
105            spea = []
106            copy_board = []  
107    def Death(self,GameBoard):
108        None
109
110        
111        
112def main():
113    pygame.init()
114
115    screen = pygame.display.set_mode(SCREEN.size)
116
117    GameBoard = [[0,0,0,0,0,0,0,0,0,0],
118                 [0,0,0,0,0,0,0,0,0,0],
119                 [0,0,0,0,0,0,0,0,0,0],
120                 [0,0,0,0,0,0,0,0,0,0],
121                 [0,0,0,0,0,0,0,0,0,0],
122                 [0,0,0,0,0,0,0,0,0,0],
123                 [0,0,0,0,0,0,0,0,0,0],
124                 [0,0,0,0,0,0,0,0,0,0],
125                 [0,0,0,0,0,0,0,0,0,0],
126                 [0,0,0,0,0,0,0,0,0,0],
127                 [0,0,0,0,0,0,0,0,0,0],
128                 [0,0,0,0,0,0,0,0,0,0],
129                 [0,0,0,0,0,0,0,0,0,0],
130                 [0,0,0,0,0,0,0,0,0,0],
131                 [0,0,0,0,0,0,0,0,0,0],
132                 [0,0,0,0,0,0,0,0,0,0],
133                 [0,0,0,0,0,0,0,0,0,0],
134                 [0,0,0,0,0,0,0,0,0,0],
135                 [0,0,0,0,0,0,0,0,0,0],
136                 [0,0,0,0,0,0,0,0,0,0],
137                 [0,0,0,0,0,0,0,0,0,0],
138                 [0,0,0,0,0,0,0,0,0,0]]
139    
140    tetorised = [[[[1,1,0,0],[0,1,1,0],[0,0,0,0],[0,0,0,0]],
141                  [[0,1,0,0],[1,1,0,0],[1,0,0,0],[0,0,0,0]],
142                  [[1,1,0,0],[0,1,1,0],[0,0,0,0],[0,0,0,0]],
143                  [[0,1,0,0],[1,1,0,0],[1,0,0,0],[0,0,0,0]]],
144                  
145                  [[[2,2,0,0],[2,2,0,0],[0,0,0,0],[0,0,0,0]],
146                   [[2,2,0,0],[2,2,0,0],[0,0,0,0],[0,0,0,0]],
147                   [[2,2,0,0],[2,2,0,0],[0,0,0,0],[0,0,0,0]],
148                   [[2,2,0,0],[2,2,0,0],[0,0,0,0],[0,0,0,0]]],
149                   
150                   [[[3,0,0,0],[3,3,3,0],[0,0,0,0],[0,0,0,0]],
151                    [[3,3,0,0],[3,0,0,0],[3,0,0,0],[0,0,0,0]],
152                    [[3,3,3,0],[0,0,3,0],[0,0,0,0],[0,0,0,0]],
153                    [[0,3,0,0],[0,3,0,0],[3,3,0,0],[0,0,0,0]]],
154                    
155                    [[[0,4,4,0],[4,4,0,0],[0,0,0,0],[0,0,0,0]],
156                     [[4,0,0,0],[4,4,0,0],[0,4,0,0],[0,0,0,0]],
157                     [[0,4,4,0],[4,4,0,0],[0,0,0,0],[0,0,0,0]],
158                     [[4,0,0,0],[4,4,0,0],[0,4,0,0],[0,0,0,0]]],
159                     
160                     [[[0,0,5,0],[5,5,5,0],[0,0,0,0],[0,0,0,0]],
161                      [[5,0,0,0],[5,0,0,0],[5,5,0,0],[0,0,0,0]],
162                      [[5,5,5,0],[5,0,0,0],[0,0,0,0],[0,0,0,0]],
163                      [[5,5,0,0],[0,5,0,0],[0,5,0,0],[0,0,0,0]]],
164                      
165                      [[[0,6,0,0],[6,6,6,0],[0,0,0,0],[0,0,0,0]],
166                       [[6,0,0,0],[6,6,0,0],[6,0,0,0],[0,0,0,0]],
167                       [[6,6,6,0],[0,6,0,0],[0,0,0,0],[0,0,0,0]],
168                       [[0,6,0,0],[6,6,0,0],[0,6,0,0],[0,0,0,0]]],
169                       
170                       [[[7,0,0,0],[7,0,0,0],[7,0,0,0],[7,0,0,0]],
171                        [[7,7,7,7],[0,0,0,0],[0,0,0,0],[0,0,0,0]],
172                        [[7,0,0,0],[7,0,0,0],[7,0,0,0],[7,0,0,0]],
173                        [[7,7,7,7],[0,0,0,0],[0,0,0,0],[0,0,0,0]]]]
174
175    
176    tetoris = Tetoris(tetorised,GameBoard,screen)
177
178    clock = pygame.time.Clock()
179
180    while (1):
181        clock.tick(120)
182        screen.fill((255,255,255))
183        tetoris.update(GameBoard)
184        tetoris.Death(GameBoard)
185        tetoris.draw(tetorised,GameBoard,screen)
186        pygame.display.update()
187        
188        for event in pygame.event.get():
189            if event.type == QUIT:
190                pygame.quit()
191                sys.exit()
192            
193            if event.type == KEYDOWN and event.key == K_ESCAPE:
194                pygame.quit()
195                sys.exit()
196            
197if __name__ == "__main__":
198    main()

試したこと・調べたこと

teratailやGoogle等で検索した
ソースコードを自分なりに変更した
知人に聞いた
その他

上記の詳細・結果

print文で問題のある場所を探したところ、Rmoveメソッドにおいて、上記の問題が起きた際、flagはaではないことが確認できました。つまり意図せずself.objectに要素が追加されているということなので古いself.objectの管理に問題がある可能性があると考えています。しかし具体的に何をすればいいかわかりません。
チャットGPTにも聞いてみましたがいまいち頼りになりませんでした。