I cannot get the restart button to work on my stopwatch. Using Pythonista on iPhone
Question: 
    import ui
    from time import *
    start = int(time())
    def stop_time(sender):
        finish = int(time())
        total_time = int(finish - start)
        button1 = str("Your time is %i seconds." % (total_time))
        sender.title = None
        sender.title = str(button1)
    

# How do I allow the restart button to change the start variable?

    
    
    def restart_time(sender):
        start = int(time())
        button2 = str("Stopwatch restarted.")
        sender.title = None
        sender.title = str(button2)
    ui.load_view('stop_time').present('sheet')
    


Answer: By default, when you assign to an identifier for the first time in a function
it creates a local variable, even if there's a global one with the same name.
Try this:

    
    
    def restart_time(sender):
        global start
        start = int(time())
        button2 = str("Stopwatch restarted.")
        sender.title = None
        sender.title = str(button2)
    

From [the relevant entry in the Python
FAQ](https://docs.python.org/2/faq/programming.html#what-are-the-rules-for-
local-and-global-variables-in-python):

> In Python, variables that are only referenced inside a function are
> implicitly global. If a variable is assigned a new value anywhere within the
> function’s body, it’s assumed to be a local. If a variable is ever assigned
> a new value inside the function, the variable is implicitly local, and you
> need to explicitly declare it as ‘global’.

