linq per quadro non riconosce un metodo

Ho quei metodi:

public int count( Guid companyId, Expression<Func> isMatch) { var filters = new Expression<Func>[]{ x => x.PriceDefinition.CompanyId == companyId, isMatch }; return GetCount(filters); } public virtual int GetCount( IEnumerable<Expression<Func>> filters) { IQueryable _query = ObjectSet; if (filters != null) { foreach (var filter in filters) { _query = _query.Where(filter); } } return _query.Count(); } 

Quando si usa:

 count(some_guid, x => x.IsMatch(entityId, inviterId, routeId, luggageTypeId)); 

Ottengo la seguente eccezione:

 LINQ to Entities does not recognize the method 'Boolean IsMatch(System.Nullable`1[System.Int64], System.Nullable`1[System.Int64], System.Nullable`1[System.Int64], System.Nullable`1[System.Int64])' method, and this method cannot be translated into a store expression. 

Qual è la ragione di questo?
Come posso risolverlo?