如何检查数据是否为map (键值对)？

def is_map(data):
    if isinstance(data, dict):
        for key in data:
            if not isinstance(key, str):
                return False
        return True
    return False

# 示例用法
data1 = {"key1": "value1", "key2": "value2"}
print(is_map(data1))  # 输出：True

data2 = {"key1": "value1", 123: "value2"}
print(is_map(data2))  # 输出：False

data3 = ["key1", "value1", "key2", "value2"]
print(is_map(data3))  # 输出：False