Improve performance and add type hints

twitch/management/commands/backup_db.py

@@ -7,6 +7,7 @@ from compression import zstd
 from datetime import datetime
 from pathlib import Path
 from typing import TYPE_CHECKING
+from typing import Protocol
 
 from django.conf import settings
 from django.core.management.base import BaseCommand
@@ -19,6 +20,15 @@ if TYPE_CHECKING:
     from argparse import ArgumentParser
 
 
+class SupportsStr(Protocol):
+    """Protocol for values that provide a string representation."""
+
+    def __str__(self) -> str: ...
+
+
+type SqlSerializable = bool | int | float | bytes | SupportsStr | None
+
+
 class Command(BaseCommand):
     """Create a compressed SQL dump of the Twitch and Kick dataset tables."""
 
@@ -285,7 +295,7 @@ def _write_postgres_dump(output_path: Path, tables: list[str]) -> None:
         raise CommandError(msg)
 
 
-def _sql_literal(value: object) -> str:
+def _sql_literal(value: SqlSerializable) -> str:
     """Convert a Python value to a SQL literal.
 
     Args:
@@ -305,7 +315,7 @@ def _sql_literal(value: object) -> str:
     return "'" + str(value).replace("'", "''") + "'"
 
 
-def _json_default(value: object) -> str:
+def _json_default(value: bytes | SupportsStr) -> str:
     """Convert non-serializable values to JSON-compatible strings.
 
     Args: