def create_project(server, project_item):
    try:
        project_item = server.projects.create(project_item)
        print('Created a new project called: %s' % project_item.name)
        return project_item
    except TSC.ServerResponseError:
        print('We have already created this project: %s' % project_item.name)
        sys.exit(1)

top_level_project = TSC.ProjectItem(name='Name', content_permissions='LockedToProjectWithoutNested')
top_level_project = create_project(server, top_level_project)

ValueError: Invalid value: LockedToProjectWithoutNested. content_permissions must be of type ContentPermissions.