def _os_bootstrap():

    names = sys.builtin_module_names

    join = None
    if 'posix' in names:
        sep = '/'
        from posix import stat
    elif 'nt' in names:
        sep = '\\'
        from nt import stat
    elif 'dos' in names:
        sep = '\\'
        from dos import stat
    elif 'os2' in names:
        sep = '\\'
        from os2 import stat
    elif 'mac' in names:
        from mac import stat
        def join(a, b):
            if a == '':
                return b
            if ':' not in a:
                a = ':' + a
            if a[-1:] != ':':
                a = a + ':'
            return a + b
    else:
        raise ImportError, 'no os specific module found'

    if join is None:
        def join(a, b, sep=sep):
            if a == '':
                return b
            lastchar = a[-1:]
            if lastchar == '/' or lastchar == sep:
                return a + b
            return a + sep + b

    global _os_stat
    _os_stat = stat

    global _os_path_join
    _os_path_join = join
The uri we should have crawled was not found, i.e. HTTP Error 404. Do
dataset/ETHPy150Open anandology/pyjamas/pyjd/imputil.py/_os_bootstrap--crossover with--dataset/ETHPy150Open retresco/Spyder/src/spyder/core/sink.py/AbstractCrawlUriSink.process_not_found