Python version elucidation

check_version.py

import sys
try:
    major, minor = sys.version_info.major, sys.version_info.minor
except AttributeError:
    major, minor = sys.version_info[:2]
if major < 2 or major == 2 and minor < 7:
    sys.stderr.write("You need at least Python 2.7 to run this program, but you only have %d.%d.\n"%(major,minor))
    sys.exit(1)
else: # only for testing this
    sys.stderr.write("You have Python %d.%d.\n"%(major,minor))