nbgrader is an automated grading system for Jupyter Notebooks, designed specifically for use with JupyterLab. It's an extension that helps instructors to efficiently grade assignments submitted as Jupyter Notebooks.
With nbgrader, instructors can define a set of rules or criteria that determine how to evaluate specific aspects of students' notebooks. These rules can include checks for correctness, style, and completion of tasks. Once the rules are defined, NBGrader can automatically apply them to each student's submission and generate detailed reports on their performance.