code: public List<PackageFile> getPackageFiles(Object projectIdOrPath, Integer packageId, int page, int perPage) throws GitLabApiException {
          Response response = get(Response.Status.OK, getPageQueryParams(page, perPage),
                  "projects", getProjectIdOrPath(projectIdOrPath), "packages", packageId, "package_files");
          return response.readEntity(new GenericType<List<PackageFile>>() {});
      }
docs: Get a list of package files of a single package for the specified page.
  
  <pre><code>GitLab Endpoint: GET /projects/:id/packages/:package_id/package_files</code></pre>
  
  @param projectIdOrPath the project in the form of an Integer(ID), String(path), or Project instance
  @param packageId the ID of the package to get the package files for
  @param page the page to get
  @param perPage the number of PackageFile instances per page
  @return a list of PackageFile instances for the specified package ID
  @throws GitLabApiException if any exception occurs