Sum two fields in a nested array in RethinkDB

The following document exists in a table in RethinkDB:

{  
   u'destination_addresses':[  
      u'1 Rockefeller Plaza,
      New York,
      NY 10020,
      USA',
      u'Meadowlands,
      PA 15301,
      USA'
   ],
   u'origin_addresses':[  
      u'1600 Pennsylvania Ave SE,
      Washington,
      DC 20003,
      USA'
   ],
   u'rows':[  
      {  
         u'elements':[  
            {  
               u'distance':{  
                  u'text':u'288 mi',
                  u'value':464087
               },
               u'duration':{  
                  u'text':u'5 hours 2 mins',
                  u'value':18142
               },
               u'status':u'OK'
            },
            {  
               u'distance':{  
                  u'text':u'266 mi',
                  u'value':428756
               },
               u'duration':{  
                  u'text':u'4 hours 6 mins',
                  u'value':14753
               },
               u'status':u'OK'
            }
         ]
      }
   ],
   u'status':u'OK'
}

I am trying to sum the 'value' field for both duration and distance (so, getting the total distance and duration for a given trip, which is what one of these documents is from the Google Maps Distance API). I have tried a great many combinations of pluck (from the nested fields documentation) but cannot seem to get this working. I'm working in Python, and thanks in advance for any help.

Does this do what you want?

document['rows'].concat_map(lambda row: row['elements'])['distance']['value'].sum()