lib/classes/Variables.js/Variables/populateService
class Variables:  populateService(processedOptions) {
    // #######################################################################
    // ## KEEP SYNCHRONIZED WITH EQUIVALENT IN ~/lib/plugins/print/print.js ##
    // #######################################################################
    this.options = processedOptions || {};

    this.loadVariableSyntax();
    // store
    const variableSyntaxProperty = this.service.provider.variableSyntax;
    // remove
    this.service.provider.variableSyntax = undefined; // otherwise matches itself
    this.service.serverless = undefined;
    return this.initialCall(() =>
      this.prepopulateService()
        .then(() =>
          this.populateObjectImpl(this.service).finally(() => {
            // restore
            this.service.serverless = this.serverless;
            this.service.provider.variableSyntax = variableSyntaxProperty;
          })
        )
        .then(() => this.service)
    );
  }