This is a weird sentence in English. However, when I translated it into Russian in my head, I got "Это продолжение", which could mean "it's a sequel" or "it's the next part" or something like that. Is this what this sentence is supposed to mean?
Another sentence that could benefit from some context, such as a question that this is the answer to.
"What is the next Harry Potter book about?" "It is a continuation (of the story)." "What's the next level of Duolingo like?" "It's a continuation (of more sentences)." "What's your new Spanish class like?" "It's a continuation (from the last book)." Not such a weird sentence when a prepositional phrase is attached to it.
Some sixty years ago, at Saturday morning Cinema for children, the film hero would be shown in some perilous situation at the end of a reel and along with a stirring voice-over you would then see "TO BE CONTINUED" - an attempt to get us to come back next week for the next instalment. I think the tactic worked quite well then and still does today, if less explicitly.
Honestly tho, it's not how Americans say "sequel" and it leaves a person feeling without footing or sort of in the air about the meaning....If I were speaking with a Spanish person, which I have done, and they met me after years, I would be happy to hear them say it is a continuation of a friendship. Or assume it is a continuation as before even if years had passed. It is preferable to having them say, "We must get to know each other again." That means there is little recognition since they see so many changes. Otherwise, "to be continued, a sequel, the following class or units....those are clear. We don't use "sequel" for classes but it's not grammatically wrong and when referring to the class, it would just be thought a clever turn of phrase. If applied to more advanced Spanish, a progression would make more sense. But I think the more bilingual or multi-lingual people become, the more these phrases blend and make sense and come to mind....and in context, are understood.