I implemented below code to extend my scm plugin for Dsl . The job gets created but the scm step is not added as expected in the created job

//file:DslExtension.java
import hudson.Extension;
import javaposse.jobdsl.dsl.helpers.ScmContext;

import javaposse.jobdsl.plugin.ContextExtensionPoint;
import javaposse.jobdsl.plugin.DslExtensionMethod;

@Extension(optional = true)
public class JobDslExtension extends ContextExtensionPoint{

@DslExtensionMethod(context = ScmContext.class)
public Object CustomMethodDsl(String hostName, int port, String testpath, String userName, String password, String testdata)

{ return new CustomClientSCM(hostName, port,testpath, userName,password, testdata); }

}

// File:Job Dsl Script

job('example') {
scm

{ CustomMethodDsl('hostName',123, 'testpath', ' userName', ' password', 'testdata') }

}