I think there is a balance to be struck. You should totally use numpy for the arrays and basic math applications. But say on the first example you use `self.X.T` what does `.T` even do? Not asking you to go into all the details, just more comments saying this transposes the array, see numpy docs <link>. It will ease people into the library if they are unfamiliar with it. You do have some good ones like `column of ones` already, but more of those kinds of things.

I would also avoid using pandas if at all possible. Its just another thing people have to learn if they are unfamiliar.