diff --git a/tableau_rest_api/methods/rest_api_base.py b/tableau_rest_api/methods/rest_api_base.py
index b14dc33..4f18509 100755
--- a/tableau_rest_api/methods/rest_api_base.py
+++ b/tableau_rest_api/methods/rest_api_base.py
@@ -1362,6 +1362,22 @@ def __init__(self, server: str, username: Optional[str] = None, password: Option
         self._request_obj: Optional[RestXmlRequest] = None
         self._request_json_obj: Optional[RestJsonRequest] = None
 
+        self.site_roles = (
+            u'Interactor',
+            u'Publisher',
+            u'SiteAdministrator',
+            u'Unlicensed',
+            u'UnlicensedWithPublish',  # This was sunset at some point
+            u'Viewer',
+            u'ViewerWithPublish',
+            u'ServerAdministrator',
+            u'ReadOnly',
+            u'Explorer',
+            u'ExplorerCanPublish',
+            u'SiteAdministratorExplorer',
+            u'Creator',
+            u'SiteAdministratorCreator'
+        )
         # Lookup caches to minimize calls
         self.username_luid_cache = {}
         self.group_name_luid_cache = {}
@@ -1498,4 +1514,4 @@ def update_server_active_directory_domain(self, domain_id: str, new_name: Option
         url = self.build_api_url("domains/{}".format(domain_id), server_level=True)
         response = self.send_update_request(url=url, request=tsr)
         self.end_log_block()
-        return response
\ No newline at end of file
+        return response