NDB: adding a route with the via= argument results in Exception: DB execute error

[n-peugnet]

I tried to use NDB to add routes with the following python code:

ndb.routes.create(dst='172.18.0.2', via={'family': AF_INET, 'addr': '172.18.0.3'})

But this results in the following error, which I believe should not happen:

Exception: DB execute error: ('SELECT f_tflags , f_tos , f_scope , f_type , f_RTA_DST , f_RTA_OIF , f_RTA_PRIORITY , f_RTA_TABLE , f_RTA_VIA , f_RTA_NEWDST FROM routes WHERE f_RTA_DST = ? AND f_family = ? AND f_dst_len = ? AND f_RTA_VIA = ? AND f_target = ?', ['172.18.0.2', <AddressFamily.AF_INET: 2>, 32, {'family': <AddressFamily.AF_INET: 2>, 'addr': '172.18.0.3'}, 'localhost']) {}

I tried with a single IP string as the via= argument, instead of the dict, but then I get the error Family AddressFamily.AF_UNSPEC not supported for RTA_VIA.