diff --git a/haralyzer/mixins.py b/haralyzer/mixins.py
index a7a93f8..2177a50 100644
--- a/haralyzer/mixins.py
+++ b/haralyzer/mixins.py
@@ -1,8 +1,9 @@
 """Mixin Objects that allow for shared methods"""
 from abc import ABC
-from collections.abc import MutableMapping
 from cached_property import cached_property
 
+from six.moves.collections_abc import MutableMapping
+
 
 class GetHeaders(object):
     """Mixin to get a header"""
@@ -43,4 +44,4 @@ def __init__(self, entry):
     # Base class gets properties that belong to both request/response
     @cached_property
     def headers(self):
-        return self.raw_entry["headers"]
\ No newline at end of file
+        return self.raw_entry["headers"]
diff --git a/requirements.txt b/requirements.txt
index 5edc5cd..ba55527 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,3 @@
 cached-property
 python-dateutil
+six == 1.15.0
diff --git a/setup.py b/setup.py
index f8867c9..8bbc53c 100644
--- a/setup.py
+++ b/setup.py
@@ -7,7 +7,9 @@
     from distutils.core import setup
 
 install_reqs = ['cached-property',
-                'python-dateutil', ]
+                'python-dateutil',
+                "six == 1.15.0"]
+
 if sys.version_info < (3, 4):
     install_reqs.extend([
         "backports.statistics",