exercise 5 in chapter 4

I think that this assertion function is comparing the array 'a' with the each elements of array 'b'.
So, I tried that the arguments `[1], [1], [1]` give to function is. The result was false.
I think that the result is true in this case.
Please tell me why this assertion function 'is' is correct?
I read this book in Japanese. If the translation is not good, could you tell me the sentences of the exercise 5 in English?

Start with exercise 5 in chapter 4 and the repository's answer for the assertion function `is`; compare the stated `[1], [1], [1]` case with the exercise wording. Done means resolving whether the answer or translation needs clarification, and documenting the explanation if maintainers decide a change is needed.

Written by the indexing model from the issue text.