feat: add load_api classmethod for loading API keys from file

- Add load_api classmethod to APIPolling class for loading API keys from file
- Support filtering out comments (lines starting with #) and empty lines
- Add default path to ~/.api for convenience
- Include proper type annotations and Path handling

Author: SepineTam

src/openai_api_polling/polling/api_polling.py

@@ -9,6 +9,8 @@
 
 from __future__ import annotations
 
+from os import PathLike
+from pathlib import Path
 from typing import List
 
 
@@ -65,6 +67,18 @@ def mask_api_key(api_key: str,
         suffix = api_key[-visible:]
         return prefix + (mask_char * mask_len) + suffix
 
+    @classmethod
+    def load_api(cls,
+                 api_file: str | PathLike = Path.home() / ".api") -> APIPolling:
+        api_file = Path(api_file).expanduser().absolute().as_posix()
+        api_keys: List[str] = []
+        with open(api_file, "r", encoding="utf-8") as f:
+            for line in f:
+                line = line.strip()
+                if line and not line.startswith("#"):  # 只添加非空行且不以#开头的行
+                    api_keys.append(line)
+        return cls(api_keys)
+
 
 if __name__ == "__main__":
     api_list = [