describes how findShipment could work for SL vertical

shipment-reducer.js

```
export const findShipments = (location, locationIsGeoLocation) => async (dispatch) => {
  dispatch(asyncRequest({reducerName}))
  const store = getStore()
  const promises = [
    store.shipment.find({location, locationIsGeoLocation})
  ]
  // If the location is a geo location we need to filter the shipments to only
  // include those that are valid locations for the users geo location. This way
  // we exclude shipments for locations that the user does not have the funder.
  // For that we need to get the locations the user can see.
  if (locationIsGeoLocation) {
    const mdApi = getMDApi()
    promises.push(
      mdApi.location.listChildren(location.id)
    )
  }
  return Promise.all(promises)
    .then(([shipments, locations]) => {
      let locationIdSet
      if (locationIsGeoLocation) {
        locationIdSet = new Set(locations.map(l => l._id))
      } else {
        locationIdSet = new Set([location.id])
      }

      const destinedShipments = shipments.filter(shipment => locationIdSet.has(shipment.destination.id) && shipment.status !== 'new')
      const originShipments = shipments.filter(shipment => locationIdSet.has(shipment.origin.id))

      shipments = [...originShipments, ...destinedShipments]

      dispatch(asyncReceive({reducerName}))
      dispatch({type: RECEIVE_SHIPMENTS, shipments})
    })
    .catch(error => dispatch(asyncReceiveError({reducerName, error})))
}
```

I've made a ticket to stating my discovery related this https://github.com/fielded/van-orga/issues/2614