block changes color if clicked on

Block.py

 '''Block object which will be used in a corsi-blocks test'''
 
 #pygame is the library for drawing
+#keyboard is the library for tracking what user does with their keyboard
 import sys
 import pygame
 import keyboard
@@ -11,36 +12,58 @@ class Block:
     #Constructor to initiate a block (square)
     #x and y -- coordinates of the top left corner
     #length -- the length of one side of the square
-    def __init__(self, x, y, length):
+    #pressed -- is the boolean variable for detecting whether a user clicked on the block
+    def __init__(self, x, y, length, pressed):
         self.x_coord = x
         self.y_coord = y
         self.length = length
+        self.pressed = pressed
 
     def draw_block(self, screen):
         '''function for drawing a block with initialized parameters'''
-        pygame.draw.rect(screen, (0, 0, 0),
-        (self.x_coord, self.y_coord, self.length, self.length),0)
+        if self.pressed:
+            pygame.draw.rect(screen, (169,169,169),
+            (self.x_coord, self.y_coord, self.length, self.length),0)
+        else:
+            pygame.draw.rect(screen, (0, 0, 0),
+            (self.x_coord, self.y_coord, self.length, self.length),0)
+
+    def clicked(self, screen, event):
+        '''function for detecting whether a user has pressed on the block'''
+        if event.type == pygame.MOUSEBUTTONDOWN and event.button == 1:
+            coord_x, coord_y = pygame.mouse.get_pos()
+            if coord_x >= self.x_coord and coord_x <= self.x_coord + self.length and coord_y >= self.y_coord and coord_y <= self.y_coord + self.length:
+                self.pressed = True
+            self.draw_block(screen)
 
 #this class will be tested, thus, we need this main method
 #as it sets the environment where we are going to test
 def main():
     '''This is MAAAAIN'''
+    #defining the screen parameters
     pygame.init()
     width = 1000
     height = 800
     pygame.display.set_mode((width, height))
     screen = pygame.display.get_surface()
     screen.fill((255,255,255))
+
+    #creating an object
+    pressed = False
+    block1 = Block(100, 100, 50, pressed)
+
+    #drawing initial block
+    block1.draw_block(screen)
+    pygame.display.update()
+
+    #checking and updating the color when the block is clicked
     while True:
-        block1 = Block(100, 100, 50)
-        block1.draw_block(screen)
-        pygame.display.update()
-        try:
-            if keyboard.is_pressed('q'):
+        for event in pygame.event.get():
+            if event.type == pygame.QUIT:
                 pygame.quit()
                 sys.exit()
-        except:
-            break
+            block1.clicked(screen, event)
+            pygame.display.update()
 
 #class functions testing
 main()