I just tried many tips in stackoverflow to solve my issue:

Failed to start mongod.service: Unit mongod.service not found

I try this: Failed to start mongod.service: Unit mongod.service not found

still nothing

I do in this page: can't install mongodb on ubuntu 16.10

and still nothing

I do on this page: https://docs.mongodb.com/manual/tutorial/install-mongodb-on-ubuntu/

it give me something, then when I update my linux, there are some word about mongodb

when I want to write: udo apt-get install -y mongodb-org

it give this:

mongodb-org : Depends: mongodb-org-shell but it is not going to be installed
           Depends: mongodb-org-server but it is not going to be installed
           Depends: mongodb-org-mongos but it is not going to be installed

when I do check with

sudo systemctl status mongodb

how to solve?

I just don't know, hopefully I can install with you advise, and run my code, thanks