python 判断平台

import os
import sys


JYTHON = sys.platform.startswith('java')
IRONPYTHON = sys.platform == 'cli'
PYPY = 'PyPy' in sys.version
PYTHON = not (JYTHON or IRONPYTHON)  # PyPY and CPython work mostly same way
PY2 = sys.version_info[0] == 2
PY3 = not PY2
UNIXY = os.sep == '/'
WINDOWS = not UNIXY

RERAISED_EXCEPTIONS = (KeyboardInterrupt, SystemExit, MemoryError)
if JYTHON:
    from java.lang import OutOfMemoryError
    RERAISED_EXCEPTIONS += (OutOfMemoryError,)


if WINDOWS:
    CASE_INSENSITIVE_FILESYSTEM = True
else:
    try:
        CASE_INSENSITIVE_FILESYSTEM = os.listdir('/tmp') == os.listdir('/TMP')
    except OSError:
        CASE_INSENSITIVE_FILESYSTEM = False