Fix doc issues

docs/requirements.txt

@@ -1,5 +1,5 @@
 #
-# This file is autogenerated by pip-compile with Python 3.10
+# This file is autogenerated by pip-compile with Python 3.11
 # by the following command:
 #
 #    pip-compile --allow-unsafe --generate-hashes --output-file=docs/requirements.txt --strip-extras docs/requirements.in

proxy/http/server/metrics.py

@@ -10,7 +10,7 @@
 """
 import os
 import glob
-from typing import TYPE_CHECKING, Any, Dict, List, Tuple, Generator
+from typing import Any, Dict, List, Tuple, Generator, cast
 from pathlib import Path
 from urllib.parse import parse_qs, urlparse
 from multiprocessing.synchronize import Lock
@@ -27,10 +27,6 @@
 )
 
 
-if TYPE_CHECKING:
-    from prometheus_client.registry import Collector
-
-
 flags.add_argument(
     '--enable-metrics',
     action='store_true',
@@ -92,12 +88,7 @@ def _set_gauge(self, name: str, value: float) -> None:
             g.write(str(value))
 
 
-def get_collector(metrics_lock: Lock) -> 'Collector':
-    """
-    Returns an instance of the `Collector` class.
-
-    :rtype: prometheus_client.core.Collector
-    """
+def get_collector(metrics_lock: Lock) -> Any:
     # pylint: disable=import-outside-toplevel
     from prometheus_client.core import Metric
     from prometheus_client.registry import Collector
@@ -195,10 +186,11 @@ class MetricsWebServerPlugin(HttpWebServerBasePlugin):
     def __init__(self, *args: Any, **kwargs: Any) -> None:
         # pylint: disable=import-outside-toplevel
         from prometheus_client.core import CollectorRegistry
+        from prometheus_client.registry import Collector
 
         super().__init__(*args, **kwargs)
         self.registry = CollectorRegistry()
-        self.registry.register(get_collector(self.flags.metrics_lock))
+        self.registry.register(cast(Collector, get_collector(self.flags.metrics_lock)))
 
     def routes(self) -> List[Tuple[int, str]]:
         if self.flags.metrics_path: