Fix and enable dangerous-default-value lint

The fix is more of an elision and the code in the changed area is
reflowed.

.pylintrc

@@ -32,6 +32,5 @@
 #TODO: Enable simplifiable-if-statement
 #TODO: Enable no-self-use
 #TODO: Enable no-member
-#TODO: Enable dangerous-default-value
 
-disable=missing-docstring,too-few-public-methods,too-many-arguments,no-init,duplicate-code,invalid-name,suppressed-message,locally-disabled,protected-access,no-name-in-module,unused-argument,fixme,wrong-import-order,no-value-for-parameter,cyclic-import,unused-variable,redefined-outer-name,unused-import,too-many-instance-attributes,broad-except,too-many-locals,too-many-lines,redefined-variable-type,next-method-called,import-error,useless-else-on-loop,too-many-return-statements,too-many-nested-blocks,super-init-not-called,simplifiable-if-statement,no-self-use,no-member,dangerous-default-value
+disable=missing-docstring,too-few-public-methods,too-many-arguments,no-init,duplicate-code,invalid-name,suppressed-message,locally-disabled,protected-access,no-name-in-module,unused-argument,fixme,wrong-import-order,no-value-for-parameter,cyclic-import,unused-variable,redefined-outer-name,unused-import,too-many-instance-attributes,broad-except,too-many-locals,too-many-lines,redefined-variable-type,next-method-called,import-error,useless-else-on-loop,too-many-return-statements,too-many-nested-blocks,super-init-not-called,simplifiable-if-statement,no-self-use,no-member

src/python/grpcio/grpc/_common.py

@@ -148,36 +148,23 @@ def fully_qualified_method(group, method):
 class CleanupThread(threading.Thread):
     """A threading.Thread subclass supporting custom behavior on join().
 
-  On Python Interpreter exit, Python will attempt to join outstanding threads
-  prior to garbage collection.  We may need to do additional cleanup, and
-  we accomplish this by overriding the join() method.
-  """
-
-    def __init__(self,
-                 behavior,
-                 group=None,
-                 target=None,
-                 name=None,
-                 args=(),
-                 kwargs={}):
+    On Python Interpreter exit, Python will attempt to join outstanding threads
+    prior to garbage collection.  We may need to do additional cleanup, and
+    we accomplish this by overriding the join() method.
+    """
+
+    def __init__(self, behavior, *args, **kwargs):
         """Constructor.
 
-    Args:
-      behavior (function): Function called on join() with a single
-          argument, timeout, indicating the maximum duration of
-          `behavior`, or None indicating `behavior` has no deadline.
-          `behavior` must be idempotent.
-      group (None): should be None.  Reseved for future extensions
-          when ThreadGroup is implemented.
-      target (function): The function to invoke when this thread is
-          run.  Defaults to None.
-      name (str): The name of this thread.  Defaults to None.
-        args (tuple[object]): A tuple of arguments to pass to `target`.
-      kwargs (dict[str,object]): A dictionary of keyword arguments to
-           pass to `target`.
-    """
-        super(CleanupThread, self).__init__(
-            group=group, target=target, name=name, args=args, kwargs=kwargs)
+        Args:
+            behavior (function): Function called on join() with a single
+                argument, timeout, indicating the maximum duration of
+                `behavior`, or None indicating `behavior` has no deadline.
+                `behavior` must be idempotent.
+            args: Positional arguments passed to threading.Thread constructor.
+            kwargs: Keyword arguments passed to threading.Thread constructor.
+        """
+        super(CleanupThread, self).__init__(*args, **kwargs)
         self._behavior = behavior
 
     def join(self, timeout=None):