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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def init_cachedir(base=None):
    '''
    Initialize the cachedir needed for Salt Cloud to keep track of minions
    '''
    if base is None:
        base = __opts__['cachedir']
    needed_dirs = (base,
                   os.path.join(base, 'requested'),
                   os.path.join(base, 'active'))
    for dir_ in needed_dirs:
        if not os.path.exists(dir_):
            os.makedirs(dir_)
        os.chmod(base, 0o755)

    return base