diff --git a/pkgs/development/python-modules/sseclient/default.nix b/pkgs/development/python-modules/sseclient/default.nix
index b446aa808b4..ebc6435bc79 100644
--- a/pkgs/development/python-modules/sseclient/default.nix
+++ b/pkgs/development/python-modules/sseclient/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, buildPythonPackage, fetchPypi
+{ stdenv, buildPythonPackage, fetchPypi, isPy27
 , requests, six
 , backports_unittest-mock, pytestCheckHook, pytestrunner }:
 
@@ -13,6 +13,8 @@ buildPythonPackage rec {
 
   propagatedBuildInputs = [ requests six ];
 
+  # some tests use python3 strings
+  doCheck = !isPy27;
   checkInputs = [ backports_unittest-mock pytestCheckHook pytestrunner ];
 
   # tries to open connection to wikipedia