docs: public static BoxRetentionPolicyAssignment.Info createAssignmentToMetadata(BoxAPIConnection api,
                                                                                 String policyID,
                                                                                 String templateID,
                                                                                 MetadataFieldFilter... filter) {
          JsonObject assignTo = new JsonObject().add("type", TYPE_METADATA).add("id", templateID);
          JsonArray filters = null;
          if (filter.length > 0) {
              filters = new JsonArray();
              for (MetadataFieldFilter f : filter) {
                  filters.add(f.getJsonObject());
              }
          }
          return createAssignment(api, policyID, assignTo, filters);
      }