address review: add type annotation, validate entry point group in test

- Add PrometheusMetricExporterConfig type annotation to
  _create_prometheus_metric_reader config parameter
- Assert entry_points is called with the correct group name
  (opentelemetry_pull_metric_exporter) in plugin loading test

Assisted-by: Claude Opus 4.6

Author: MikeGoldsmith

opentelemetry-sdk/src/opentelemetry/sdk/_configuration/_meter_provider.py

@@ -20,6 +20,9 @@
 from opentelemetry.sdk._configuration.models import (
     ExemplarFilter as ExemplarFilterConfig,
 )
+from opentelemetry.sdk._configuration.models import (
+    ExperimentalPrometheusMetricExporter as PrometheusMetricExporterConfig,
+)
 from opentelemetry.sdk._configuration.models import (
     ExporterDefaultHistogramAggregation,
     ExporterTemporalityPreference,
@@ -391,7 +394,9 @@ def _create_periodic_metric_reader(
     )
 
 
-def _create_prometheus_metric_reader(config) -> MetricReader:
+def _create_prometheus_metric_reader(
+    config: PrometheusMetricExporterConfig,
+) -> MetricReader:
     """Create a PrometheusMetricReader from config.
 
     Dynamically imports the prometheus exporter package to avoid a hard

opentelemetry-sdk/tests/_configuration/test_meter_provider.py

@@ -382,9 +382,12 @@ def test_pull_no_exporter_raises(self):
     def test_pull_plugin_loads_via_entry_point(self):
         mock_reader = MagicMock()
         mock_class = MagicMock(return_value=mock_reader)
+        mock_entry_points = MagicMock(
+            return_value=[MagicMock(**{"load.return_value": mock_class})]
+        )
         with patch(
             "opentelemetry.sdk._configuration._common.entry_points",
-            return_value=[MagicMock(**{"load.return_value": mock_class})],
+            mock_entry_points,
         ):
             config = MeterProviderConfig(
                 readers=[
@@ -401,6 +404,10 @@ def test_pull_plugin_loads_via_entry_point(self):
             provider = create_meter_provider(config)
         self.assertEqual(len(provider._sdk_config.metric_readers), 1)
         mock_class.assert_called_once_with(port=8080)
+        mock_entry_points.assert_called_once_with(
+            group="opentelemetry_pull_metric_exporter",
+            name="my_custom_reader",
+        )
 
     def test_pull_plugin_not_found_raises(self):
         with patch(