bug fix with user functions

hp4155/memristor (Version 4.1)/help.py

@@ -206,7 +206,7 @@ def sweep(start,stop,step,comp,integration,device): #step cannot be negative
 
 #sampling check
 def sampling_check(voltage,device):
-    
+    device.del_user_functions()
     parameters ={
         'mode' : 'LIN',
         'hold': 0,