AssignmentsReportsGenerator::columns()

	protected function columns()
	{
		return [
			'user_id'         => $this->column('user_id'),
			'user'            => $this->column('user'),
			'course_id'       => $this->column('course_id'),
			'course'          => $this->column('course'),
			'assignment'            => [
				'label'     => __( 'Assignment', 'buddyboss' ),
				'sortable'  => false,
				'order_key' => '',
			],
			'completion_date' => [
				'label'     => __( 'Graded Date', 'buddyboss' ),
				'sortable'  => true,
				'order_key' => 'assignment_modify_date',
			],
			'updated_date' => [
				'label'     => __( 'Uploaded Date', 'buddyboss' ),
				'sortable'  => true,
				'order_key' => 'assignment_post_date',
			],
			'score'           => [
				'label'     => __( 'Score', 'buddyboss' ),
				'sortable'  => false,
				'order_key' => '',
			],
		];
	}