diff --git a/mriqc/reports/group.py b/mriqc/reports/group.py
index 2417dd95..f893bc14 100644
--- a/mriqc/reports/group.py
+++ b/mriqc/reports/group.py
@@ -200,6 +200,7 @@ def gen_html(csv_file, mod, csv_failed=None, out_file=None):
                 None,
             ),
         ],
+        "dwi": [],
     }
 
     if csv_file.suffix == ".csv":
@@ -208,13 +209,9 @@ def gen_html(csv_file, mod, csv_failed=None, out_file=None):
         )
 
         id_labels = list(set(BIDS_COMP) & set(dataframe.columns.ravel().tolist()))
-        dataframe["label"] = dataframe[id_labels].apply(
-            _format_labels, args=(id_labels,), axis=1
-        )
+        dataframe["label"] = dataframe[id_labels].apply(_format_labels, args=(id_labels,), axis=1)
     else:
-        dataframe = pd.read_csv(
-            csv_file, index_col=False, sep="\t", dtype={"bids_name": object}
-        )
+        dataframe = pd.read_csv(csv_file, index_col=False, sep="\t", dtype={"bids_name": object})
         dataframe = dataframe.rename(index=str, columns={"bids_name": "label"})
 
     nPart = len(dataframe)
@@ -271,9 +268,7 @@ def gen_html(csv_file, mod, csv_failed=None, out_file=None):
                 )
             ).read(),
             "d3_js": open(
-                pkgrf(
-                    "mriqc", op.join("data", "reports", "embed_resources", "d3.min.js")
-                )
+                pkgrf("mriqc", op.join("data", "reports", "embed_resources", "d3.min.js"))
             ).read(),
             "boxplots_css": open(
                 pkgrf(