diff --git a/py/hexagram/cluster_c.pyx b/py/hexagram/cluster_c.pyx
index ffa38b9..eedbd4a 100644
--- a/py/hexagram/cluster_c.pyx
+++ b/py/hexagram/cluster_c.pyx
@@ -24,7 +24,7 @@ cdef extern from *:
     """
     cdef extern PyTypeObject *ctx_type
 
-cdef class hexagram_cluster_py:
+cdef class Cluster_py:
     cdef object _obj
 
     def __cinit__(self, double rpm_min, double rpm_redline, double rpm_max):