diff --git a/doc/specs/in-progress/make_paste_ini_config_optional.rst b/doc/specs/in-progress/make_paste_ini_config_optional.rst
index 0e06d20..a797924 100644
--- a/doc/specs/in-progress/make_paste_ini_config_optional.rst
+++ b/doc/specs/in-progress/make_paste_ini_config_optional.rst
@@ -60,20 +60,20 @@ Assignee(s)
 -----------
 
 Primary assignee:
-  <launchpad-id or None>
+  dbelova
 
 Work Items
 ----------
 
-- Modify  osprofiler.web.WsgiMiddleware to make ``hmac_keys`` optional
+- Modify osprofiler.web.WsgiMiddleware to make ``hmac_keys`` optional (done)
 
 - Add alternative way to setup osprofiler.web.WsgiMiddleware, e.g. extra
-  argument to enable() hmac_keys
+  argument hmac_keys to enable() method (done)
 
-- Cut new release 0.3.1
+- Cut new release 0.3.1 (tbd)
 
-- Fix the code in all projects: remove api-paste.ini arguments and add
-  extra argument to osprofiler.web.enable
+- Fix the code in all projects: remove api-paste.ini arguments and use
+  osprofiler.web.enable with extra argument (tbd)
 
 
 Dependencies
diff --git a/osprofiler/web.py b/osprofiler/web.py
index 053c132..209cc27 100644
--- a/osprofiler/web.py
+++ b/osprofiler/web.py
@@ -40,6 +40,7 @@ def get_trace_id_headers():
 
 
 _DISABLED = False
+_HMAC_KEYS = None
 
 
 def disable():
@@ -52,16 +53,17 @@ def disable():
     _DISABLED = True
 
 
-def enable():
+def enable(hmac_keys=None):
     """Enable middleware."""
-    global _DISABLED
+    global _DISABLED, _HMAC_KEYS
     _DISABLED = False
+    _HMAC_KEYS = utils.split(hmac_keys or "")
 
 
 class WsgiMiddleware(object):
     """WSGI Middleware that enables tracing for an application."""
 
-    def __init__(self, application, hmac_keys, enabled=False):
+    def __init__(self, application, hmac_keys=None, enabled=False):
         """Initialize middleware with api-paste.ini arguments.
 
         :application: wsgi app
@@ -100,7 +102,7 @@ class WsgiMiddleware(object):
 
         trace_info = utils.signed_unpack(request.headers.get("X-Trace-Info"),
                                          request.headers.get("X-Trace-HMAC"),
-                                         self.hmac_keys)
+                                         _HMAC_KEYS or self.hmac_keys)
 
         if not self._trace_is_valid(trace_info):
             return request.get_response(self.application)
diff --git a/tests/test_web.py b/tests/test_web.py
index 578559c..94ab5c4 100644
--- a/tests/test_web.py
+++ b/tests/test_web.py
@@ -270,6 +270,33 @@ class WebMiddlewareTestCase(test.TestCase):
         self.assertEqual("yeah!", middleware(request))
         self.assertEqual(mock_profiler_init.call_count, 0)
 
+    @mock.patch("osprofiler.web.profiler.init")
+    def test_wsgi_middleware_enable_via_python(self, mock_profiler_init):
+        request = mock.MagicMock()
+        request.get_response.return_value = "yeah!"
+        request.url = "someurl"
+        request.host_url = "someurl"
+        request.path = "path"
+        request.query_string = "query"
+        request.method = "method"
+        request.scheme = "scheme"
+        hmac_key = 'super_secret_key2'
+
+        pack = utils.signed_pack({"base_id": "1", "parent_id": "2"}, hmac_key)
+        request.headers = {
+            "a": "1",
+            "b": "2",
+            "X-Trace-Info": pack[0],
+            "X-Trace-HMAC": pack[1]
+        }
+
+        web.enable('super_secret_key1,super_secret_key2')
+        middleware = web.WsgiMiddleware("app", enabled=True)
+        self.assertEqual("yeah!", middleware(request))
+        mock_profiler_init.assert_called_once_with(hmac_key=hmac_key,
+                                                   base_id="1",
+                                                   parent_id="2")
+
     def test_disable(self):
         web.disable()
         self.assertTrue(web._DISABLED)