diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 9331b7c..50714ef 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -878,7 +878,7 @@
 It is possible to create shared objects using shared memory which can be
 inherited by child processes.
 
-.. function:: Value(typecode_or_type[, *args, lock]])
+.. function:: Value(typecode_or_type, *args[, lock])
 
    Return a :mod:`ctypes` object allocated from shared memory.  By default the
    return value is actually a synchronized wrapper for the object.
@@ -960,7 +960,7 @@
 
    *typecode_or_type* determines the type of the returned object: it is either a
    ctypes type or a one character typecode of the kind used by the :mod:`array`
-   module.  */*args* is passed on to the constructor for the type.
+   module.  *\*args* is passed on to the constructor for the type.
 
    Note that setting and getting the value is potentially non-atomic -- use
    :func:`Value` instead to make sure that access is automatically synchronized
@@ -970,7 +970,7 @@
    attributes which allow one to use it to store and retrieve strings -- see
    documentation for :mod:`ctypes`.
 
-.. function:: Array(typecode_or_type, size_or_initializer[, *args[, lock]])
+.. function:: Array(typecode_or_type, size_or_initializer, *args[, lock])
 
    The same as :func:`RawArray` except that depending on the value of *lock* a
    process-safe synchronization wrapper may be returned instead of a raw ctypes
diff --git a/Lib/multiprocessing/sharedctypes.py b/Lib/multiprocessing/sharedctypes.py
index b94cd52..1976277 100644
--- a/Lib/multiprocessing/sharedctypes.py
+++ b/Lib/multiprocessing/sharedctypes.py
@@ -66,9 +66,12 @@
     Return a synchronization wrapper for a Value
     '''
     obj = RawValue(typecode_or_type, *args)
-    if lock is None:
+    if lock is False:
+        return obj
+    if lock in (True, None):
         lock = RLock()
-    assert hasattr(lock, 'acquire')
+    if not hasattr(lock, 'acquire'):
+        raise AttributeError("'%r' has no method 'acquire'" % lock)
     return synchronized(obj, lock)
 
 def Array(typecode_or_type, size_or_initializer, **kwds):
@@ -79,9 +82,12 @@
     if kwds:
         raise ValueError('unrecognized keyword argument(s): %s' % list(kwds.keys()))
     obj = RawArray(typecode_or_type, size_or_initializer)
-    if lock is None:
+    if lock is False:
+        return obj
+    if lock in (True, None):
         lock = RLock()
-    assert hasattr(lock, 'acquire')
+    if not hasattr(lock, 'acquire'):
+        raise AttributeError("'%r' has no method 'acquire'" % lock)
     return synchronized(obj, lock)
 
 def copy(obj):
diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py
index a8600c0..4e5d759 100644
--- a/Lib/test/test_multiprocessing.py
+++ b/Lib/test/test_multiprocessing.py
@@ -830,10 +830,16 @@
         obj3 = val3.get_obj()
         self.assertEqual(lock, lock3)
 
-        arr4 = self.RawValue('i', 5)
+        arr4 = self.Value('i', 5, lock=False)
         self.assertFalse(hasattr(arr4, 'get_lock'))
         self.assertFalse(hasattr(arr4, 'get_obj'))
 
+        self.assertRaises(AttributeError, self.Value, 'i', 5, lock='navalue')
+
+        arr5 = self.RawValue('i', 5)
+        self.assertFalse(hasattr(arr5, 'get_lock'))
+        self.assertFalse(hasattr(arr5, 'get_obj'))
+
 
 class _TestArray(BaseTestCase):
 
@@ -888,9 +894,15 @@
         obj3 = arr3.get_obj()
         self.assertEqual(lock, lock3)
 
-        arr4 = self.RawArray('i', list(range(10)))
+        arr4 = self.Array('i', range(10), lock=False)
         self.assertFalse(hasattr(arr4, 'get_lock'))
         self.assertFalse(hasattr(arr4, 'get_obj'))
+        self.assertRaises(AttributeError,
+                          self.Array, 'i', range(10), lock='notalock')
+
+        arr5 = self.RawArray('i', range(10))
+        self.assertFalse(hasattr(arr5, 'get_lock'))
+        self.assertFalse(hasattr(arr5, 'get_obj'))
 
 #
 #
diff --git a/Misc/NEWS b/Misc/NEWS
index fee788f..b1c5d7f 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -135,6 +135,12 @@
 - Issue #4959: inspect.formatargspec now works for keyword only arguments
   without defaults.
 
+- Issue #4449: AssertionError in mp_benchmarks.py, caused by an underlying issue
+  in sharedctypes.py.
+
+- Issue #1225107: inspect.isclass() returned True for instances with a custom
+  __getattr__.
+
 - Issue #3826 and #4791: The socket module now closes the underlying socket
   appropriately when it is being used via socket.makefile() objects
   rather than delaying the close by waiting for garbage collection to do it.