Pitfall09-time.time()

******************************************************************** before assignment
time.time()
time is refered before assignment

reason:duplication variable name
somewhere in the code:
for time in lst:
  ......
   ......
   
******************************************************************** need to create 
X_single is not created
reason:
above the code
X_signle = round(function(x1,x2) # miss close ")"