def get_stream_xcorr(name_or_func=None, concurrency=None):
    """
    Return a function for performing normalized cross correlation on lists of
    streams.

    :param name_or_func:
        Either a name of a registered function or a callable that implements
        the standard array_normxcorr signature.
    :param concurrency:
        Optional concurrency strategy, options are below.

    :return: A callable with the interface of stream_normxcorr

    :Concurrency options:
        - multithread - use a threadpool for concurrency;
        - multiprocess - use a process pool for concurrency;
        - concurrent - use a customized concurrency strategy for the function,
          if not defined threading will be used.
    """
    func = _get_registerd_func(name_or_func)

    concur = concurrency or 'stream_xcorr'
    if not hasattr(func, concur):
        msg = '%s does not support concurrency %s' % (func.__name__, concur)
        raise ValueError(msg)
    return getattr(func, concur)
Return a function for performing normalized cross correlation on lists of
    streams.

    :param name_or_func:
        Either a name of a registered function or a callable that implements
        the standard array_normxcorr signature.
    :param concurrency:
        Optional concurrency strategy, options are below.

    :return: A callable with the interface of stream_normxcorr

    :Concurrency options:
        - multithread - use a threadpool for concurrency;
        - multiprocess - use a process pool for concurrency;
        - concurrent - use a customized concurrency strategy for the function,
          if not defined threading will be used.