diff --git a/optimizely/optimizely_config.py b/optimizely/optimizely_config.py
index e429c3c4..52887d43 100644
--- a/optimizely/optimizely_config.py
+++ b/optimizely/optimizely_config.py
@@ -21,7 +21,7 @@ def __init__(self, revision, experiments_map, features_map, datafile=None):
         self.revision = revision
         self.experiments_map = experiments_map
         self.features_map = features_map
-        self.datafile = datafile
+        self._datafile = datafile
 
     def get_datafile(self):
         """ Get the datafile associated with OptimizelyConfig.
@@ -29,7 +29,7 @@ def get_datafile(self):
         Returns:
             A JSON string representation of the environment's datafile.
         """
-        return self.datafile
+        return self._datafile
 
 
 class OptimizelyExperiment(object):
diff --git a/optimizely/project_config.py b/optimizely/project_config.py
index 344be542..8d608890 100644
--- a/optimizely/project_config.py
+++ b/optimizely/project_config.py
@@ -40,7 +40,7 @@ def __init__(self, datafile, logger, error_handler):
         """
 
         config = json.loads(datafile)
-        self._datafile = datafile
+        self._datafile = u'{}'.format(datafile)
         self.logger = logger
         self.error_handler = error_handler
         self.version = config.get('version')
diff --git a/tests/test_optimizely_config.py b/tests/test_optimizely_config.py
index 0ccbeb0d..695cdc91 100644
--- a/tests/test_optimizely_config.py
+++ b/tests/test_optimizely_config.py
@@ -456,7 +456,7 @@ def setUp(self):
                 }
             },
             'revision': '1',
-            'datafile': json.dumps(self.config_dict_with_features)
+            '_datafile': json.dumps(self.config_dict_with_features)
         }
 
         self.actual_config = self.opt_config_service.get_config()