code: func (o *LaunchSpecification) SetBackendServiceConfig(v *BackendServiceConfig) *LaunchSpecification {
  	if o.BackendServiceConfig = v; o.BackendServiceConfig == nil {
  		o.nullFields = append(o.nullFields, "BackendServiceConfig")
  	}
  	return o
  }
docs: // SetBackendServices sets the backend services to use with the group.