refactor(*): dedup while keeping order using dict.fromkeys()

Previously, I was not in favor of the approach because it was a quite
new feature in Python 3.7+ (CPython 3.6+). Newness always means
confusion to some extent. But it is no longer a new feature after all
these years. So I am going to adopt such an elegant approach.

Signed-off-by: Rongrong <i@rong.moe>

src/env.py

@@ -119,7 +119,7 @@ def __compare_version(version1: str, version2: str) -> tuple[int, list[Union[int
                  os.path.join(os.path.abspath('.'), '.env'))
 if is_self_run_as_a_whole_package:
     dot_env_paths = (os.path.normpath(os.path.join(self_path, '..', '.env')),) + dot_env_paths
-for dot_env_path in sorted(set(dot_env_paths), key=dot_env_paths.index):
+for dot_env_path in dict.fromkeys(dot_env_paths):  # remove duplicates while keeping the order
     if os.path.isfile(dot_env_path):
         load_dotenv(dot_env_path, override=True)
         logger.info(f'Found .env file at "{dot_env_path}", loaded')

src/parsing/medium.py

@@ -253,8 +253,8 @@ class Medium(AbstractMedium):
     def __init__(self, urls: Union[str, list[str]], type_fallback_urls: Optional[Union[str, list[str]]] = None):
         super().__init__()
         urls = urls if isinstance(urls, list) else [urls]
-        # dedup, should not use a set because sequence is important
-        self.urls: list[str] = sorted(set(urls), key=urls.index)
+        # dedup while keeping the order
+        self.urls: list[str] = list(dict.fromkeys(urls))
         self.original_urls: tuple[str, ...] = tuple(self.urls)
         self.chosen_url: Optional[str] = self.urls[0]
         self._server_change_count: int = 0