Address issues reported by static checkers

docs/conf.py

@@ -3,7 +3,6 @@
 # For the full list of built-in configuration values, see the documentation:
 # https://www.sphinx-doc.org/en/master/usage/configuration.html
 
-# pylint: disable=import-error
 import os
 import sys
 from collections.abc import Sequence

scrapy/core/engine.py

@@ -269,6 +269,7 @@ class ExecutionEngine:
             self._slot.nextcall.schedule()
             return
         except CloseSpider as exception:
+            assert self.spider is not None  # typing
             self.close_spider(self.spider, reason=exception.reason)
             return
 

tests/test_closespider.py

@@ -120,7 +120,7 @@ class TestCloseSpider(TestCase):
 
             async def yield_seeds(self):
                 raise CloseSpider("foo")
-                yield
+                yield  # pylint: disable=unreachable
 
         close_reasons = []