diff --git a/libmc/_client.pyx b/libmc/_client.pyx
index 6c130297..b7162b78 100644
--- a/libmc/_client.pyx
+++ b/libmc/_client.pyx
@@ -1191,6 +1191,7 @@ cdef class PyClientPool(PyClientSettings):
             self.release(worker)
 
     # repeated from PyClient because cython can't handle fused types in classes
+    # https://github.com/cython/cython/issues/3283
     cdef connect(self):
         return _update_servers(self._imp, self.servers, True)
 
diff --git a/tests/test_client_pool.py b/tests/test_client_pool.py
index 707c43f8..6344199f 100644
--- a/tests/test_client_pool.py
+++ b/tests/test_client_pool.py
@@ -18,8 +18,9 @@ def test_acquire(self):
 
     def test_pool_client_misc(self, i=0):
         with self.pool.client() as mc:
-            tid = str(mc._get_current_thread_ident() + (i,))
-            f, t = 'foo ' + tid, 'tuiche ' + tid
+            tid = mc._get_current_thread_ident() + (i,)
+            tid = "_".join(map(str, tid))
+            f, t = 'foo_' + tid, 'tuiche_' + tid
             mc.get_multi([f, t])
             mc.delete(f)
             mc.delete(t)