refactor mm training

Former-commit-id: 179c0558699e287cbf38a2d73bff47e86d589c5a

src/llamafactory/data/__init__.py

@@ -12,13 +12,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .collator import KTODataCollatorWithPadding, PairwiseDataCollatorWithPadding, SFTDataCollatorWith4DAttentionMask
+from .collator import (
+    CustomDataCollatorForSeq2Seq,
+    KTODataCollatorWithPadding,
+    PairwiseDataCollatorWithPadding,
+    SFTDataCollatorWith4DAttentionMask,
+)
 from .data_utils import Role, split_dataset
 from .loader import get_dataset
 from .template import TEMPLATES, Template, get_template_and_fix_tokenizer
 
 
 __all__ = [
+    "CustomDataCollatorForSeq2Seq",
     "KTODataCollatorWithPadding",
     "PairwiseDataCollatorWithPadding",
     "SFTDataCollatorWith4DAttentionMask",