code: def getMultiple(self, layers, where="1 = 1", fields=[], srid='4326', layer_name_field=None):
          
          features = []
          for layer in layers:
              get_fields = fields or self.enumerate_layer_fields(layer)
              this_layer = self.get(layer, where, get_fields, False, srid).get('features')
              if layer_name_field:
                  descriptor = self.get_descriptor_for_layer(layer)
                  layer_name = descriptor.get('name')
                  for feature in this_layer:
                      feature['properties'][layer_name_field] = layer_name
              features += this_layer
          return {
              'type': "FeatureCollection",
              'features': features
          }
docs: Get a bunch of layers and concatenate them together into one. This is useful if you
          have a map with layers for, say, every year named stuff_2014, stuff_2013, stuff_2012. Etc.
  
          Optionally, you can stuff the source layer name into a field of your choosing.
  
          >>> arc.getMultiple([0, 3, 5], layer_name_field='layer_src_name')