diff --git a/aertb/core/__init__.py b/aertb/core/__init__.py
index 6681579..2db461c 100644
--- a/aertb/core/__init__.py
+++ b/aertb/core/__init__.py
@@ -1,4 +1,4 @@
 from .file_loader import FileLoader
 from .viz import make_gif
 from .types import event_dtype
-from .hdf5tools import HDF5FileIterator
\ No newline at end of file
+from .hdf5tools import HDF5FileIterator, HDF5File
diff --git a/aertb/core/hdf5tools.py b/aertb/core/hdf5tools.py
index ef1b0b6..43fa0a4 100644
--- a/aertb/core/hdf5tools.py
+++ b/aertb/core/hdf5tools.py
@@ -271,4 +271,4 @@ def fixed_train_test_split(self, n_train, n_test, rand=23):
             random.Random(rand).shuffle(train_samples)
             random.Random(rand + 1).shuffle(test_samples)
 
-        return HDF5FileIterator(self.file, train_samples), HDF5FileIterator(self.file, test_samples)
+        return HDF5FileIterator(self.file, train_samples), HDF5FileIterator(self.file, test_samples)
\ No newline at end of file
diff --git a/aertb/core/types.py b/aertb/core/types.py
index cb9a132..5f5dc69 100644
--- a/aertb/core/types.py
+++ b/aertb/core/types.py
@@ -21,6 +21,6 @@
                                ('x_', np.float32), ('y_', np.float32),
                                ('z_', np.float32), ('d_', np.float32)])
 
-Sample = namedtuple('Sample', ['name', 'label', 'events'])
+Sample = namedtuple('Sample', ['group', 'name'])
 EvSample = namedtuple('EvSample', ['label', 'name', 'events'])
 # =============================================================================
\ No newline at end of file