docs: public CompletableFuture<Revision> addPerUserPermission(Author author, String projectName,
                                                              String repoName, User member,
                                                              Collection<Permission> permission) {
          requireNonNull(author, "author");
          requireNonNull(projectName, "projectName");
          requireNonNull(repoName, "repoName");
          requireNonNull(member, "member");
          requireNonNull(permission, "permission");
  
          return getProject(projectName).thenCompose(project -> {
              ensureProjectMember(project, member);
              return addPermissionAtPointer(author, projectName,
                                            perUserPermissionPointer(repoName, member.id()), permission,
                                            "Add permission of '" + member.id() +
                                            "' as '" + permission + "' to the project " + projectName);
          });
      }