diff --git a/niworkflows/interfaces/nibabel.py b/niworkflows/interfaces/nibabel.py
index d7d7546b22d..37668703329 100644
--- a/niworkflows/interfaces/nibabel.py
+++ b/niworkflows/interfaces/nibabel.py
@@ -234,7 +234,7 @@ def _run_interface(self, runtime):
                 continue
             else:
                 raise ValueError(
-                    "Input image has an incorrect number of dimensions" f" ({ndim})."
+                    f"Input image has an incorrect number of dimensions ({ndim})."
                 )
 
         img_4d = nb.concat_images(
diff --git a/niworkflows/viz/utils.py b/niworkflows/viz/utils.py
index c3ba7e668d9..cc932b9e2d0 100644
--- a/niworkflows/viz/utils.py
+++ b/niworkflows/viz/utils.py
@@ -566,7 +566,7 @@ def plot_melodic_components(
                 tr = tr / 1000000.0
             elif units[-1] != "sec":
                 NIWORKFLOWS_LOG.warning(
-                    "Unknown repetition time units " "specified - assuming seconds"
+                    "Unknown repetition time units specified - assuming seconds"
                 )
         else:
             NIWORKFLOWS_LOG.warning(