diff --git a/html5lib/_utils.py b/html5lib/_utils.py
index 03f0dab7..91252f2c 100644
--- a/html5lib/_utils.py
+++ b/html5lib/_utils.py
@@ -1,6 +1,5 @@
 from __future__ import absolute_import, division, unicode_literals
 
-import sys
 from types import ModuleType
 
 from six import text_type
@@ -13,11 +12,9 @@
 
 __all__ = ["default_etree", "MethodDispatcher", "isSurrogatePair",
            "surrogatePairToCodepoint", "moduleFactoryFactory",
-           "supports_lone_surrogates", "PY27"]
+           "supports_lone_surrogates"]
 
 
-PY27 = sys.version_info[0] == 2 and sys.version_info[1] >= 7
-
 # Platforms not supporting lone surrogates (\uD800-\uDFFF) should be
 # caught by the below test. In general this would be any platform
 # using UTF-16 as its encoding of unicode strings, such as
diff --git a/html5lib/html5parser.py b/html5lib/html5parser.py
index f8309e14..dd8ba6f7 100644
--- a/html5lib/html5parser.py
+++ b/html5lib/html5parser.py
@@ -1,5 +1,5 @@
 from __future__ import absolute_import, division, unicode_literals
-from six import with_metaclass, viewkeys, PY3
+from six import with_metaclass, viewkeys
 
 import types
 from collections import OrderedDict
@@ -2707,10 +2707,7 @@ def processEndTag(self, token):
 
 
 def adjust_attributes(token, replacements):
-    if PY3 or _utils.PY27:
-        needs_adjustment = viewkeys(token['data']) & viewkeys(replacements)
-    else:
-        needs_adjustment = frozenset(token['data']) & frozenset(replacements)
+    needs_adjustment = viewkeys(token['data']) & viewkeys(replacements)
     if needs_adjustment:
         token['data'] = OrderedDict((replacements.get(k, k), v)
                                     for k, v in token['data'].items())