Im trying to compare two ids to get the lower in ascii.
The ids are alphanumeric `"836778436K"`, `"K8474874"`....

I tried with

```java
lowerSupplyDeliveryTerm.stream()
                       .map(dto -> dto.provider.nif)
                       .min(SupplyDto::provider.nif)

```

The `SupplyDto` class is

```java
public class SupplyDto {
    public String id;
    public long version;

    public SupplierProviderDto provider = new SupplierProviderDto();
    public SuppliedSparePartDto sparePart = new SuppliedSparePartDto();

    public double price;
    public int deliveryTerm;

    public static class SupplierProviderDto {
        public String id;
        public String nif;
        public String name;

    }

    public static class SuppliedSparePartDto {
        public String id;
        public String code;
        public String description;

    }

}

```

The problem is that I don't know which lambda function should I introduce in the min function to compare the nifs of the providers in the dto.

Thanks in advance.