diff --git a/bob/learn/em/test/test_ivector.py b/bob/learn/em/test/test_ivector.py
index 6f8ca98cb9f60797655d53d2f4cb69d2ee389ce7..7e1abd6759cb92972fadcc8c3414acb57733806b 100644
--- a/bob/learn/em/test/test_ivector.py
+++ b/bob/learn/em/test/test_ivector.py
@@ -107,7 +107,7 @@ class IVectorMachinePy():
     return TtSigmaInvNT
 
   def forward(self, gmmstats):
-    if self.m_ubm and not (self.m_t == None) and not (self.m_sigma == None):
+    if self.m_ubm and self.m_t is not None and self.m_sigma is not None:
       N = gmmstats.n
       F = gmmstats.sum_px