diff --git a/playwright/README.md b/playwright/README.md
index b57e3c3..c46b732 100644
--- a/playwright/README.md
+++ b/playwright/README.md
@@ -41,92 +41,117 @@ if __name__ == "__main__":
 
 ```python
 # db.py
+
 import sqlite3, json
 
+
 class DB(sqlite3.Connection):
     def __init__(self, db_name=".db.sqlite"):
         super().__init__(db_name)
         with self:
-            self.execute('''
+            self.execute(
+                """
                 CREATE TABLE IF NOT EXISTS kv_store
                 (key TEXT PRIMARY KEY, value BLOB)
-            ''')
+            """
+            )
 
     def __setitem__(self, key, value):
-        if not isinstance(value, bytes): value = json.dumps(value)
+        if not isinstance(value, bytes):
+            value = json.dumps(value)
         with self:
-            cur = self.execute('''
+            cur = self.execute(
+                """
                 INSERT OR REPLACE INTO kv_store
                 (key, value) VALUES (?, ?)
-            ''', (key, value))
+            """,
+                (key, value),
+            )
             return {"modified_count": cur.rowcount}
 
     def __getitem__(self, key):
         with self:
-            result = self.execute('''
+            result = self.execute(
+                """
                 SELECT value FROM kv_store
                 WHERE key = ?
-            ''', (key,)).fetchone()
+            """,
+                (key,),
+            ).fetchone()
         if result:
             if isinstance(result[0], str):
-                try: return json.loads(result[0])
-                except json.JSONDecodeError: pass
+                try:
+                    return json.loads(result[0])
+                except json.JSONDecodeError:
+                    pass
             return result[0]
 
     def delete(self, key):
         with self:
-            cur = self.execute('''
+            cur = self.execute(
+                """
                 DELETE FROM kv_store 
                 WHERE key = ?
-            ''', (key,))
+            """,
+                (key,),
+            )
             return {"deleted_count": cur.rowcount}
 
-    def keys(self, pattern='*'):
-        pattern = pattern.translate(str.maketrans({
-            '\\': '\\\\', '%': '\\%', '_': '\\_', '*': '%', '?': '_'
-        }))
+    def keys(self, pattern="*"):
+        pattern = pattern.translate(
+            str.maketrans({"\\": "\\\\", "%": "\\%", "_": "\\_", "*": "%", "?": "_"})
+        )
         with self:
-            result = self.execute('''
+            result = self.execute(
+                """
                 SELECT key FROM kv_store
                 WHERE key LIKE ? ESCAPE '\\'
-            ''', (pattern,)).fetchall()
+            """,
+                (pattern,),
+            ).fetchall()
         return [row[0] for row in result]
 
-    def __repr__(self): return repr(self.keys())
+    def __repr__(self):
+        return repr(self.keys())
 
     def exists(self, key):
         with self:
-            cur = self.execute('''
+            cur = self.execute(
+                """
                 SELECT 1 FROM kv_store
                 WHERE key = ?
                 LIMIT 1
-            ''', (key,))
+            """,
+                (key,),
+            )
             return bool(cur.fetchone())
 
-if __name__ == '__main__':
+
+if __name__ == "__main__":
     db = DB()
 
     # 문자열 저장 및 조회
-    db['hello'] = 'world'
-    print(db['hello'])  # 출력: world (str 타입)
-    
-    # 숫자 저장 및 조회
-    db['number'] = 42
-    print(db['number'])  # 출력: 42 (int 타입)
-    
-    # 바이너리 데이터 저장 및 조회
-    db['binary'] = b'binary data'
-    print(db['binary'])  # 출력: b'binary data' (bytes 타입)
-    
-    # 복잡한 객체 저장
-    complex_obj = {'name': 'John', 'age': 30, 'city': 'New York'}
-    db['complex'] = complex_obj
-    loaded_obj = db['complex']
-    print(loaded_obj)  # 출력: {'name': 'John', 'age': 30, 'city': 'New York'} (dict 타입)
-    
-    db['test_key'] = 'test_value'
-    
-    print(db.exists('test_key'))  # True
-    print(db.exists('non_existent_key'))  # False
+    db["hello"] = "world"
+    print(db["hello"])  # 출력: world (str 타입)
 
+    # 숫자 저장 및 조회
+    db["number"] = 42
+    print(db["number"])  # 출력: 42 (int 타입)
+
+    # 바이너리 데이터 저장 및 조회
+    db["binary"] = b"binary data"
+    print(db["binary"])  # 출력: b'binary data' (bytes 타입)
+
+    # 복잡한 객체 저장
+    complex_obj = {"name": "John", "age": 30, "city": "New York"}
+    db["complex"] = complex_obj
+    loaded_obj = db["complex"]
+    print(
+        loaded_obj
+    )  # 출력: {'name': 'John', 'age': 30, 'city': 'New York'} (dict 타입)
+
+    db["test_key"] = "test_value"
+
+    print(db.exists("test_key"))  # True
+    print(db.exists("non_existent_key"))  # False
 ```