Simplify the declarations of the Python code.

codes/python/chapter_hashing/array_hash_map.py

@@ -23,7 +23,7 @@ class ArrayHashMap:
 
     def hash_func(self, key: int) -> int:
         """哈希函数"""
-        index: int = key % 100
+        index = key % 100
         return index
 
     def get(self, key: int) -> str:
@@ -56,7 +56,7 @@ class ArrayHashMap:
 
     def key_set(self) -> list[int]:
         """获取所有键"""
-        result: list[int] = []
+        result = []
         for pair in self.buckets:
             if pair is not None:
                 result.append(pair.key)
@@ -64,7 +64,7 @@ class ArrayHashMap:
 
     def value_set(self) -> list[str]:
         """获取所有值"""
-        result: list[str] = []
+        result = []
         for pair in self.buckets:
             if pair is not None:
                 result.append(pair.val)