Exiting Python?

Okay so I have a program that I've written in Python 3. It creates a file log and writes it to a file. If there are no logs, the file doesn't get created. Later in the program it calls the file, but the file doesn't exist. I want it to catch the exception when it can't open the file and just exit the script and do nothing else but I can't figure out how. The exit and quit commands don't do what I want. I've tried to Google it but I can't find anything on it. Can someone lead me in the right direction please?

os.path.isfile(\path\to\file)

os.path.exists(\path\to\file)

Try this:

import sys
for x in range(1, 300):
        print x
        if(x==20):
                sys.exit(0)```

try:
        open('File that doesnt exist', 'r')
except IOError:
        print "Can't open file."
        exit(1)

and a quick google

try:
    f = open('myfile.txt')
    s = f.readline()
    i = int(s.strip())
except IOError as (errno, strerror):
    print "I/O error({0}): {1}".format(errno, strerror)
except ValueError:
    print "Could not convert data to an integer."
except:
    print "Unexpected error:", sys.exc_info()[0]
    raise```

From http://docs.python.org/tutorial/errors.html