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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 open_data_source(source):
 """Open a GWF file source into a `lalframe.XLALFrStream` object Parameters source : `str`, `file`, `list` Data source to read. Returns ------- stream : `lalframe.FrStream` An open `FrStream`. Raises ------ ValueError If the input format cannot be identified. """

    if isinstance(source, FILE_LIKE):
        source = source.name
    if isinstance(source, CacheEntry):
        source = source.path

    # read cache file
    if (isinstance(source, string_types) and
            source.endswith(('.lcf', '.cache'))):
        return lalframe.FrStreamCacheOpen(lal.CacheImport(source))

    # read glue cache object
    if isinstance(source, list) and is_cache(source):
        cache = lal.Cache()
        for entry in file_list(source):
            cache = lal.CacheMerge(cache, lal.CacheGlob(*os.path.split(entry)))
        return lalframe.FrStreamCacheOpen(cache)

    # read lal cache object
    if isinstance(source, lal.Cache):
        return lalframe.FrStreamCacheOpen(source)

    # read single file
    if isinstance(source, string_types):
        return lalframe.FrStreamOpen(*map(str, os.path.split(source)))

    raise ValueError("Don't know how to open data source of type %r"
                     % type(source))