I trying to use an example from docs . Copy and paste both of

class Utilities implements Serializable {
     def steps     Utilities(steps) {{color:#000043}this.steps = steps}
     def mvn(args) {
     steps.sh "${steps.tool 'Maven'{color}}/bin/mvn -o ${args}"     }
}

and

@Library('lib@trunk/pipelines/jlib/trunk') _
import derivative.Utilities
def utils = new Utilities(this)
node {
     stage ('some') {
     utils.mvn 'clean package'    }
}

and then get the following output:

ERROR: No tool named Maven found

I have tried to susbstitute 'Maven' to 'git' , because i'd like to pass git into shared lib. But getting same message:

ERROR: No tool named git found

I cannot understand, what exactly is steps.sh? Is it bash script?