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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 kml_region(map_source, z, x, y):
 """KML region fetched by a Google Earth network link. """

    map = app.config["mapsources"][map_source]
    kml_doc = KMLRegion(app.config["url_formatter"], map, app.config["LOG_TILES_PER_ROW"],
                        z, x, y)
    return kml_response(kml_doc)