issue_server101.py 文件源码

def is_future_feature(object):
    """
    Return True if C{object} results from a C{from __future__ import feature}
    statement.
    """
    # Guard from unexpected implementation changes of the __future__ module.
    global __future_check_works
    if __future_check_works is not None:
        if __future_check_works:
            import __future__
            return isinstance(object, __future__._Feature)
        else:
            return False
    else:
        __future_check_works = True
        try:
            return is_future_feature(object)
        except:
            __future_check_works = False
            log.warning("Troubles inspecting __future__. Python implementation"
                        " may have been changed.")
            return False