how to overcome time limit exceeded in python code example

Example: is TLE means my code is correct but taking more time to computr

TLE actually means that your program excedes the time limit for a 
particular test file. So, as soon as the time limit is exceeded the
program stops executing and you don’t know whether your program 
gives AC or not.
So, best practice is to optimize your program as much as possible.
Even, then it gives TLE, then go for different approach.