diff --git a/kafka/coordinator/consumer.py b/kafka/coordinator/consumer.py
index a45909ad1..b8d1378be 100644
--- a/kafka/coordinator/consumer.py
+++ b/kafka/coordinator/consumer.py
@@ -6,7 +6,7 @@
 import time
 
 from kafka.coordinator.base import BaseCoordinator, Generation
-from kafka.coordinator.assignors.abstract import RebalanceProtocol
+from kafka.coordinator.assignors.abstract import RebalanceProtocol, AbstractPartitionAssignor
 from kafka.coordinator.assignors.range import RangePartitionAssignor
 from kafka.coordinator.assignors.roundrobin import RoundRobinPartitionAssignor
 from kafka.coordinator.assignors.sticky.sticky_assignor import StickyPartitionAssignor
@@ -115,7 +115,10 @@ def __init__(self, client, subscription, **configs):
 
         self._assignors = {}
         for klass in self.config['assignors']:
-            assignor = klass()
+            if isinstance(klass, AbstractPartitionAssignor):
+                assignor = klass
+            else:
+                assignor = klass()
             self._assignors[assignor.name] = assignor
         # KIP-429: all configured assignors must agree on a single
         # RebalanceProtocol mode. Mixing EAGER and COOPERATIVE