Simple Unit of Work implementation

MyClass.cs

using System;

namespace ClassLibrary
{
    public interface IDependency
    {
        void SomeMethod(string s);
    }

    public class MyClass
    {
        private readonly IDependency dependency;
        private readonly Func<IUnitOfWork> startNewUnitOfWork;

        public MyClass(IDependency dependency,
            Func<IUnitOfWork> startNewUnitOfWork)
        {
            this.dependency = dependency;
            this.startNewUnitOfWork = startNewUnitOfWork;
        }

        public void DoWork()
        {
            using (var uow = startNewUnitOfWork())
            {
                uow.Begin(() => dependency.SomeMethod("hi"));
            }
        }
    }
}

UnitOfWork.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NHibernate;
using NHibernate.Context;

namespace ClassLibrary
{
    public interface IUnitOfWork : IDisposable
    {
        void Begin();
        void Commit();
        void RollBack();

        void Begin(Action action);
    }

    //Implementation
    public class UnitOfWork : IUnitOfWork
    {
        private readonly ISessionFactory sessionFactory;
        private ISession currentSession;
        private ITransaction currentTransaction;

        public UnitOfWork(ISessionFactory sessionFactory)
        {
            this.sessionFactory = sessionFactory;
        }

        public void Begin()
        {
            currentSession = sessionFactory.OpenSession();
            CurrentSessionContext.Bind(currentSession);
            currentTransaction = currentSession.BeginTransaction();
        }

        public void Commit()
        {
            currentTransaction.Commit();
            CurrentSessionContext.Unbind(sessionFactory);
        }

        public void RollBack()
        {
            currentTransaction.Rollback();
            CurrentSessionContext.Unbind(sessionFactory);
        }

        public void Dispose()
        {
            currentTransaction.Dispose();
            currentSession.Dispose();
        }

        public void Begin(Action action)
        {
            try
            {
                Begin();
                action.Invoke();
                Commit();
            }
            catch (Exception ex)
            {
                RollBack();
                throw ex;
            }
        }

    }
}