Hello, everyone

I am using a piece of self-modifying code for a college project.

Here it is:

import datetime
import inspect
import re
import sys

def main():
    # print the time it is last run
    lastrun = 'Mon Jun  8 16:31:27 2009'

    print "This program was last run at ",
    print lastrun

    # read in the source code of itself
    srcfile = inspect.getsourcefile(sys.modules[__name__])
    f = open(srcfile, 'r')
    src = f.read()
    f.close()

    # modify the embedded timestamp
    timestamp = datetime.datetime.ctime(datetime.datetime.now())
    match = re.search("lastrun = '(.*)'", src)
    if match:
        src = src[:match.start(1)] + timestamp + src[match.end(1):]

    # write the source code back
    f = open(srcfile, 'w')
    f.write(src)
    f.close()

if __name__=='__main__':
    main()

Unfortunately, it doesn't work. Error returned:

# This is the script's output
This program is last run at  Mon Jun  8 16:31:27 2009
# This is the error message
Traceback (most recent call last):
  File "C:\Users\Rui Gomes\Desktop\teste.py", line 30, in <module>
    main()
  File "C:\Users\Rui Gomes\Desktop\teste.py", line 13, in main
    srcfile = inspect.getsourcefile(sys.modules[__name__])
  File "C:\Python31\lib\inspect.py", line 439, in getsourcefile
    filename = getfile(object)
  File "C:\Python31\lib\inspect.py", line 401, in getfile
    raise TypeError('{!r} is a built-in module'.format(object))
TypeError: <module '__main__' (built-in)> is a built-in module

I'd be thankful for any solutions.