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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 import_locations(self, osm_file):
 """Import OSM data files. ``import_locations()`` returns a list of ``Node`` and ``Way`` objects. It expects data files conforming to the `OpenStreetMap 0.5 DTD`_, which is XML such as:: <?xml version="1.0" encoding="UTF-8"?> <osm version="0.5" generator="upoints/0.9.0"> <node id="0" lat="52.015749" lon="-0.221765" user="jnrowe" visible="true" timestamp="2008-01-25T12:52:11+00:00" /> <node id="1" lat="52.015761" lon="-0.221767" visible="true" timestamp="2008-01-25T12:53:00+00:00"> <tag k="created_by" v="hand" /> <tag k="highway" v="crossing" /> </node> <node id="2" lat="52.015754" lon="-0.221766" user="jnrowe" visible="true" timestamp="2008-01-25T12:52:30+00:00"> <tag k="amenity" v="pub" /> </node> <way id="0" visible="true" timestamp="2008-01-25T13:00:00+0000"> <nd ref="0" /> <nd ref="1" /> <nd ref="2" /> <tag k="ref" v="My Way" /> <tag k="highway" v="primary" /> </way> </osm> The reader uses the :mod:`ElementTree` module, so should be very fast when importing data. The above file processed by ``import_locations()`` will return the following `Osm` object:: Osm([ Node(0, 52.015749, -0.221765, True, "jnrowe", utils.Timestamp(2008, 1, 25, 12, 52, 11), None), Node(1, 52.015761, -0.221767, True, utils.Timestamp(2008, 1, 25, 12, 53), None, {"created_by": "hand", "highway": "crossing"}), Node(2, 52.015754, -0.221766, True, "jnrowe", utils.Timestamp(2008, 1, 25, 12, 52, 30), {"amenity": "pub"}), Way(0, [0, 1, 2], True, None, utils.Timestamp(2008, 1, 25, 13, 00), {"ref": "My Way", "highway": "primary"})], generator="upoints/0.9.0") Args: osm_file (iter):
 OpenStreetMap data to read Returns: Osm: Nodes and ways from the data .. _OpenStreetMap 0.5 DTD: http://wiki.openstreetmap.org/wiki/OSM_Protocol_Version_0.5/DTD """

        self._osm_file = osm_file
        data = utils.prepare_xml_read(osm_file, objectify=True)

        # This would be a lot simpler if OSM exports defined a namespace
        if not data.tag == 'osm':
            raise ValueError("Root element %r is not `osm'" % data.tag)
        self.version = data.get('version')
        if not self.version:
            raise ValueError('No specified OSM version')
        elif not self.version == '0.5':
            raise ValueError('Unsupported OSM version %r' % data)

        self.generator = data.get('generator')

        for elem in data.getchildren():
            if elem.tag == 'node':
                self.append(Node.parse_elem(elem))
            elif elem.tag == 'way':
                self.append(Way.parse_elem(elem))