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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 merge_extinfo(host, extinfo):
 """Merge extended host information into a host :param host: the host to edit :type host: alignak.objects.host.Host :param extinfo: the external info we get data from :type extinfo: alignak.objects.hostextinfo.HostExtInfo :return: None """

        # Note that 2d_coords and 3d_coords are never merged, so not usable !
        properties = ['notes', 'notes_url', 'icon_image', 'icon_image_alt',
                      'vrml_image', 'statusmap_image']
        # host properties have precedence over hostextinfo properties
        for prop in properties:
            if getattr(host, prop) == '' and getattr(extinfo, prop) != '':
                setattr(host, prop, getattr(extinfo, prop))