docs: private static BoxRetentionPolicyAssignment.Info createAssignment(BoxAPIConnection api, String policyID,
                                                                        JsonObject assignTo, JsonArray filter) {
          URL url = ASSIGNMENTS_URL_TEMPLATE.build(api.getBaseURL());
          BoxJSONRequest request = new BoxJSONRequest(api, url, "POST");
  
          JsonObject requestJSON = new JsonObject()
                  .add("policy_id", policyID)
                  .add("assign_to", assignTo);
  
          if (filter != null) {
              requestJSON.add("filter_fields", filter);
          }
  
          request.setBody(requestJSON.toString());
          BoxJSONResponse response = (BoxJSONResponse) request.send();
          JsonObject responseJSON = JsonObject.readFrom(response.getJSON());
          BoxRetentionPolicyAssignment createdAssignment
              = new BoxRetentionPolicyAssignment(api, responseJSON.get("id").asString());
          return createdAssignment.new Info(responseJSON);
      }