检测系统版本、python发行版本
import sys
is_jython = sys.platform.startswith('java')
is_pypy = hasattr(sys, 'pypy_version_info')
is_win = (sys.platform == 'win32')
is_cygwin = (sys.platform == 'cygwin')
is_darwin = (sys.platform == 'darwin')
import sys
is_jython = sys.platform.startswith('java')
is_pypy = hasattr(sys, 'pypy_version_info')
is_win = (sys.platform == 'win32')
is_cygwin = (sys.platform == 'cygwin')
is_darwin = (sys.platform == 'darwin')