code: public Observable<RunbookDraftInner> getAsync(String resourceGroupName, String automationAccountName, String runbookName) {
          return getWithServiceResponseAsync(resourceGroupName, automationAccountName, runbookName).map(new Func1<ServiceResponse<RunbookDraftInner>, RunbookDraftInner>() {
              @Override
              public RunbookDraftInner call(ServiceResponse<RunbookDraftInner> response) {
                  return response.body();
              }
          });
      }
docs: Retrieve the runbook draft identified by runbook name.
  
  @param resourceGroupName Name of an Azure Resource group.
  @param automationAccountName The name of the automation account.
  @param runbookName The runbook name.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the RunbookDraftInner object