code: def get_stream_xcorr(name_or_func=None, concurrency=None):
      
      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)
docs: 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.