code: def get_copy_from(self):
          
          # Create a mapping of source ARs for copy
          copy_from = self.request.form.get("copy_from", "").split(",")
          # clean out empty strings
          copy_from_uids = filter(lambda x: x, copy_from)
          out = dict().fromkeys(range(len(copy_from_uids)))
          for n, uid in enumerate(copy_from_uids):
              ar = self.get_object_by_uid(uid)
              if ar is None:
                  continue
              out[n] = ar
          logger.info("get_copy_from: uids={}".format(copy_from_uids))
          return out
docs: Returns a mapping of UID index -> AR object