error with variables 3.8

[buran]

on line 62 you assign to err. Thus err in the body of get_time() is different variable (i.e. with local scope) than the err in the global scope. obviously it's not the else part that is executed and on line 69 err is not defined.
to resolve it you can add global err statement at the top of get_time() function.
However note that using global variables is bad practice. So the best would be to refactor your code.