unable to run a function from imported groovy library getting "No such property: git for class: groovy.lang.Binding"

Team,

I am learning groovy and created a simple one but getting this error running pipeline on jenkins. not sure what it really means

+ echo inside MAIN in stage Formatting
inside MAIN in stage Formatting
[Pipeline] }
[Pipeline] // container
Post stage

Also:   org.jenkinsci.plugins.workflow.actions.ErrorAction$ErrorId: c454d67d-2abf-4f99-aa8b-281ea186c072
groovy.lang.MissingPropertyException: No such property: git for class: groovy.lang.Binding
    at groovy.lang.Binding.getVariable(Binding.java:63)
    at groovy.lang.Binding.getVariable(Binding.java:63)
    at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onGetProperty(SandboxInterceptor.java:285)
    at org.kohsuke.groovy.sandbox.impl.Checker$7.call(Checker.java:375)
    at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:379)
    at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:355)
    at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:355)
    at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:355)
    at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.getProperty(SandboxInvoker.java:29)
    at com.cloudbees.groovy.cps.impl.PropertyAccessBlock.rawGet(PropertyAccessBlock.java:20)
    at WorkflowScript.run(WorkflowScript:181)
    at ___cps.transform___(Native Method)

my library is

checkoutGit.groovy

def call(Map config) {
    println "Starting the script...1"
}

Jenkinsfile is

    pipeline {
        agent {
            label 'stuff1'
        }
        options {
            ansiColor('xterm')
            parallelsAlwaysFailFast()
            buildDiscarder(logRotator(artifactDaysToKeepStr: '30'))
            throttleJobProperty(
                throttleEnabled: true,
                throttleOption: 'project',
                maxConcurrentPerNode: 1,
                maxConcurrentTotal: 30,
            )
        }

        stages {
            stage('Formatting and Style') {
                agent {
                    label 'stuff2'
                }
                when { expression { !params.Refresh } }
                steps {
                    container('main') {
                        sh 'echo "inside MAIN in stage Formatting"'
                        checkoutGit(
                            credentialsId: git-ssh,
                            remoteUrl: 'ssh://git.t.com:123',
                            refspec: '+$GERRIT_REFSPEC:$GERRIT_REFSPEC',
                            branch: 'main'
                        )
                    }
                 }
             }
         }

You need to quote this string, otherwise it looks like you are subtracting variable ssh from variable git

credentialsId: 'git-ssh',