SNOW-1526475: fix type hint for private_key (#1996)

Author: sfc-gh-aling

DESCRIPTION.md

@@ -12,6 +12,7 @@ Source code is also available at: https://github.com/snowflakedb/snowflake-conne
   - Set default connection timeout of 10 seconds and socket read timeout of 10 minutes for HTTP calls in file transfer.
   - Optimized `to_pandas()` performance by fully parallel downloading logic.
   - Fixed a bug that specifying client_session_keep_alive_heartbeat_frequency in snowflake-sqlalchemy could crash the connector.
+  - Fixed incorrect type hint of connection parameter `private_key`.
   - Added support for connectivity to multiple domains.
   - Bumped keyring dependency from g>=23.1.0,<25.0.0 to g>=23.1.0,<26.0.0
 

src/snowflake/connector/connection.py

@@ -183,7 +183,7 @@ def _get_private_bytes_from_file(
     "backoff_policy": (DEFAULT_BACKOFF_POLICY, Callable),
     "passcode_in_password": (False, bool),  # Snowflake MFA
     "passcode": (None, (type(None), str)),  # Snowflake MFA
-    "private_key": (None, (type(None), str, RSAPrivateKey)),
+    "private_key": (None, (type(None), bytes, RSAPrivateKey)),
     "private_key_file": (None, (type(None), str)),
     "private_key_file_pwd": (None, (type(None), str, bytes)),
     "token": (None, (type(None), str)),  # OAuth or JWT Token