export declare class HealthKitIdentifier {
    private readonly value;
    private constructor();
    static create(identifier: string): HealthKitIdentifier;
    private validate;
    toString(): string;
    equals(other: HealthKitIdentifier): boolean;
}
export declare class HealthKitUnit {
    private readonly value;
    private constructor();
    static create(unit: string): HealthKitUnit;
    private validate;
    toString(): string;
    equals(other: HealthKitUnit): boolean;
}
export declare class DateRange {
    readonly startDate: Date;
    readonly endDate: Date;
    constructor(startDate: Date, endDate: Date);
    private validate;
    getDurationInDays(): number;
}