code: func GetTrustedClusterSchema(extensionSchema string) string {
  	var trustedClusterSchema string
  	if extensionSchema == "" {
  		trustedClusterSchema = fmt.Sprintf(TrustedClusterSpecSchemaTemplate, RoleMapSchema, "")
  	} else {
  		trustedClusterSchema = fmt.Sprintf(TrustedClusterSpecSchemaTemplate, RoleMapSchema, ","+extensionSchema)
  	}
  	return fmt.Sprintf(V2SchemaTemplate, MetadataSchema, trustedClusterSchema, DefaultDefinitions)
  }
docs: // GetTrustedClusterSchema returns the schema with optionally injected
  // schema for extensions.