mypy: Minor zthumbor annotation changes.

- Any->Text in helpers.py;
- Remove ignore and add generic params.

revert thumbor except type.

zthumbor/loaders/helpers.py

@@ -35,7 +35,7 @@ else:
     secrets_file.read(os.path.join(DEPLOY_ROOT, "zproject/dev-secrets.conf"))
 
 def get_secret(key):
-    # type: (str) -> Any
+    # type: (str) -> Optional[Text]
     if secrets_file.has_option('secrets', key):
         return secrets_file.get('secrets', key)
     return None

zthumbor/loaders/zloader.py

@@ -19,9 +19,9 @@ def get_not_found_result():
     result.successful = False
     return result
 
-@return_future  # type: ignore # This was giving mypy error for missing generic datatype?
+@return_future
 def load(context, url, callback):
-    # type: (Context, str, Callable) -> None
+    # type: (Context, str, Callable[..., Any]) -> None
     url = urllib.parse.unquote(url)
     url_params = get_url_params(url)
     source_type = url_params.get('source_type')