+/* Python 3 added internal structure to the various object headers, and
+ * defined a new macro `PyVarObject_HEAD_INIT' to initialize variable-length
+ * static instances correctly. Define it if it's not already here.
+ */
+#ifndef PyVarObject_HEAD_INIT
+# define PyVarObject_HEAD_INIT(super, sz) PyObject_HEAD_INIT(super) sz,
+#endif
+