My code was working correctly till yesterday and I was able to fetch tweets, from GetSearch(), but now it is returning empty list, though I check my credentials are correct
Is something changed recently??  
Thank you
They might have a limit of requests in a certain amount of time or they had a failure on the system. You can ask for new credentials to see if the problem was the first one and try getting the tweets with them.
python-twitter GetSearch giving empty list