hmmm.....well, you could, if you have a keyboard, a midi cable, and a computer recording interface with a midi in, connect the keyboard to the midi in, bring of a midi track, and record you playing the best on your keyboard.
How I do it is I downloaded the free version of Anvil studio[ google it.] I make it in anvil, export it a a midi o-format file[ something like that] and then import it into cubase.