SliceFixture with AutoMapper

[TDK1964]

My Create handler uses AutoMapper to map from command to entity.

public async Task<int> Handle(Command command, CancellationToken cancellationToken)
            {
                var entity = _mapper.Map<ExampleEntity>(command);
                await _db.ExampleEntity.AddAsync(entity, cancellationToken);
                await _db.SaveChangesAsync(cancellationToken);
                return entity.Id;
            }

My test looks like this

var command = new Create.Command
{
    Name = "Example 1",
     ...
};
var id = await _fixture.SendAsync(command, mapper);
id.ShouldNotBeNull();

When I run the test I get "Object reference not set to an instance of an object." because _maper is null;
I know I probably need to modify the SliceFixture but can't figure out what to do.

[TDK1964]

Could anyone help?