Is there a phrase that sounds like "perform our cell"?

It sounds like the lecturer is saying

Before solving the puzzle, let's write a second version of this function that is more compact. We will call this function random walk 2. We will perform our cell and programmers duty and write a docstring.

I am confused about the last sentence. Writing a docstring is one of the duties of programmers; this is easy to understand. What does "perform our cell" mean? I searched this phrase on many online dictionaries and got no results.

Could someone give a clue?

As Jim says in the comments, "perform our solemn programmer's duty and write a docstring."

One's solemn duty is doing one's duty:

Made with deep sincerity or invoking the force of a religion.

In this case it's a hyperbole, saying that it's the deeply sincere duty of programmers to write a docstring.