code: func (f *FilterOp) GeoDistanceRange(from string, to string, fields ...GeoField) *FilterOp {
  	f.GeoDistRangeMap = make(map[string]interface{})
  	f.GeoDistRangeMap["from"] = from
  	f.GeoDistRangeMap["to"] = to
  
  	for _, val := range fields {
  		f.GeoDistRangeMap[val.Field] = val.GeoLocation
  	}
  
  	return f
  }
docs: // GeoDistanceRange will add a GEO DISTANCE RANGE op to the filter.
  // from: minimum distance in ES distance format, i.e. "100km" or "100mi".
  // to: maximum distance in ES distance format, i.e. "100km" or "100mi".
  // fields: an array of GeoField origin coordinates. Only one coor