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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 extract_feed( inpath: str, outpath: str, view: View, config: nx.DiGraph = None ) -> str: """Extract a subset of a GTFS zip into a new file"""

    config = default_config() if config is None else config
    config = remove_node_attributes(config, "converters")
    feed = load_feed(inpath, view, config)
    return write_feed_dangerously(feed, outpath)