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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 _CreateLineStringForShape(self, parent, shape):
 """Create a KML LineString using coordinates from a shape. Args: parent: The parent ElementTree.Element instance. shape: The transitfeed.Shape instance. Returns: The LineString ElementTree.Element instance or None if coordinate_list is empty. """

    coordinate_list = [(longitude, latitude) for
                       (latitude, longitude, distance) in shape.points]
    return self._CreateLineString(parent, coordinate_list)