Make types compatible with older Python versions

docs/settings.md

@@ -21,6 +21,9 @@ Supported variables: `year`, `month`, `day` and `timestamp`.
 
 ```python
 WACZ_SOURCE_URL = "s3://scrapy-webarchive/archive.wacz"
+
+# Allows multiple sources, comma seperated.
+WACZ_SOURCE_URL = "s3://scrapy-webarchive/archive.wacz,/path/to/archive.wacz"
 ```
 
 This setting defines the location of the WACZ file that should be used as a source for the crawl job.

scrapy_webarchive/wacz.py

@@ -60,8 +60,6 @@ def get_wacz_fname(self) -> str:
 
 class MultiWaczFile:
     """
-    Multiple WACZ files
-
     The MultiWACZ file format is not yet finalized, hence instead of pointing to a
     MultiWACZ file, this just works with the multiple WACZ files.
 
@@ -96,8 +94,6 @@ def iter_warc(self):
 
 class WaczFile:
     """
-    WACZ file.
-
     Handles looking up pages in the index, and iterating over all pages in the index.
     Can also iterate over all entries in each WARC embedded in the archive.
     """

scrapy_webarchive/warc.py

@@ -1,4 +1,5 @@
 import socket
+from typing import List, Tuple
 import uuid
 from datetime import datetime, timezone
 from io import BytesIO
@@ -42,7 +43,7 @@ def write_record(
         self, 
         url: str, 
         record_type: str, 
-        headers: list[tuple[str, str]], 
+        headers: List[Tuple[str, str]], 
         warc_headers: StatusAndHeaders, 
         content_type: str, 
         content: str,