Help with Groovy syntax

[Chris Fouts]

I'm 4 days old new to Groovy. I bought a book, but I just want to learn
what this syntax mean for today.

We use Groovy to run a Jenkins file in our Jenkins build. One stage has
these statements in it.

    def mainScmDetails

    stage("Checkout") {

        mainScmDetails = checkout scm

        dir("some-dir") {

            git url: 'g...@domain.com/path/project.git', credentialsId:
'some_creds', branch: 'develop'

        }

    }


Does this define a code block named mainScmDetails? Does the statement...

mainScmDetails = checkout scm

...call two functions, namely, checkout and scm?

Thanks,

Chris