/**
 * Validates the provided labels to ensure they are an array of strings and that each label
 * is a valid value within the specified enums (`UsedNodeLabels` or `UsedDatasourceLabels`).
 *
 * @param labels - The input to validate, expected to be an array of strings.
 * @throws {InvalidRequestError} If `labels` is not an array.
 * @throws {InvalidRequestError} If any label in the array is not a valid value in the combined enums.
 */
export declare const validateNodeLabels: (labels: unknown) => void;
/**
 * Validate a graph edge label.
 *
 * The value is first checked for presence (not `undefined`/`null`), then for type (`string`).
 * The string is normalised using `toLocaleLowerCase()` and validated against the `UsedEdgeLabels` enum.
 *
 * @param label - The value to validate; expected to be a string representing an edge label.
 *
 * @throws {InvalidRequestError} If `label` is `undefined` or `null`.
 * @throws {InvalidRequestError} If `label` is not a `string`.
 * @throws {InvalidRequestError} If the normalised label is not one of the supported values in `UsedEdgeLabels`.
 *
 * @example
 * validateEdgeLabel('CONNECTS'); // succeeds if 'connects' exists in UsedEdgeLabels
 *
 * @remarks
 * Membership is determined via `isInEnum` and error messages include the allowed values (via `enumCombineValuesToString`).
 */
export declare const validateEdgeLabel: (label: unknown) => void;