diff --git a/python/example/demo.py b/python/example/demo.py
index c024e6882..e046696c6 100755
--- a/python/example/demo.py
+++ b/python/example/demo.py
@@ -11,7 +11,7 @@ dtrain = xgb.DMatrix('agaricus.txt.train')
 dtest = xgb.DMatrix('agaricus.txt.test')
 
 # specify parameters via map, definition are same as c++ version
-param = {'bst:max_depth':4, 'bst:eta':1, 'silent':1, 'loss_type':2 }
+param = {'bst:max_depth':2, 'bst:eta':1, 'silent':1, 'loss_type':2 }
 
 # specify validations set to watch performance
 evallist  = [(dtest,'eval'), (dtrain,'train')]
@@ -23,7 +23,15 @@ preds = bst.predict( dtest )
 labels = dtest.get_label()
 print 'error=%f' % (  sum(1 for i in xrange(len(preds)) if int(preds[i]>0.5)!=labels[i]) /float(len(preds)))
 bst.save_model('0001.model')
+# dump model
+bst.dump_model('dump.raw.txt')
+# dump model with feature map
+bst.dump_model('dump.raw.txt','featmap.txt')
 
+# beta: interact mode
+bst.set_param('bst:interact:expand',4)
+bst.update_interact( dtrain, 'update', 0)
+bst.dump_model('dump.raw2.txt')
 
 ###
 # build dmatrix in python iteratively
diff --git a/python/xgboost.py b/python/xgboost.py
index 7c795dd8c..0e8d8fb0b 100644
--- a/python/xgboost.py
+++ b/python/xgboost.py
@@ -95,12 +95,26 @@ class Booster:
             assert isinstance(d,DMatrix)
         dmats = ( ctypes.c_void_p  * len(cache) )(*[ ctypes.c_void_p(d.handle) for d in cache])
         self.handle = xglib.XGBoosterCreate( dmats, len(cache) )
-        for k, v in params.iteritems():
-            xglib.XGBoosterSetParam( self.handle, ctypes.c_char_p(k), ctypes.c_char_p(str(v)) )        
+        self.set_param( params )
+    def set_param(self, params,pv=None):
+        if isinstance(params,dict):
+            for k, v in params.iteritems():
+                xglib.XGBoosterSetParam( self.handle, ctypes.c_char_p(k), ctypes.c_char_p(str(v)) )        
+        elif isinstance(params,str) and pv != None:
+            xglib.XGBoosterSetParam( self.handle, ctypes.c_char_p(params), ctypes.c_char_p(str(pv)) )
+        else:
+            for k, v in params:
+                xglib.XGBoosterSetParam( self.handle, ctypes.c_char_p(k), ctypes.c_char_p(str(v)) )             
     def update(self, dtrain):
         """ update """
         assert isinstance(dtrain, DMatrix)
         xglib.XGBoosterUpdateOneIter( self.handle, dtrain.handle )
+    def update_interact(self, dtrain, action, booster_index=None):
+        """ beta: update with specified action"""
+        assert isinstance(dtrain, DMatrix)
+        if booster_index != None:
+            self.set_param('interact:booster_index', str(booster_index))
+        xglib.XGBoosterUpdateInteract( self.handle, dtrain.handle, ctypes.c_char_p(str(action)) )
     def eval_set(self, evals, it = 0):
         for d in evals:
             assert isinstance(d[0], DMatrix)
diff --git a/python/xgboost_python.cpp b/python/xgboost_python.cpp
index d0db37740..b02f7d8ea 100644
--- a/python/xgboost_python.cpp
+++ b/python/xgboost_python.cpp
@@ -210,5 +210,13 @@ extern "C"{
         static_cast<Booster*>(handle)->DumpModel( fo, featmap, false );
         fclose( fo );
     }
+
+    void XGBoosterUpdateInteract( void *handle, void *dtrain, const char *action ){
+        Booster *bst = static_cast<Booster*>(handle);
+        DMatrix *dtr = static_cast<DMatrix*>(dtrain);        
+        bst->CheckInit(); dtr->CheckInit(); 
+        std::string act( action );
+        bst->UpdateInteract( act, *dtr );
+    }
 };
 
diff --git a/python/xgboost_python.h b/python/xgboost_python.h
index 9088f37d6..351a7ad6b 100644
--- a/python/xgboost_python.h
+++ b/python/xgboost_python.h
@@ -157,6 +157,13 @@ extern "C"{
      * \param fmap  name to fmap can be empty string
      */    
     void XGBoosterDumpModel( void *handle, const char *fname, const char *fmap );
+    /*! 
+     * \brief interactively update model: beta
+     * \param handle handle
+     * \param dtrain training data
+     * \param action action name
+     */        
+    void XGBoosterUpdateInteract( void *handle, void *dtrain, const char* action );   
 };
 #endif