diff --git a/spyrit/core/meas.py b/spyrit/core/meas.py
index 42b8d8fb..19099840 100644
--- a/spyrit/core/meas.py
+++ b/spyrit/core/meas.py
@@ -1485,8 +1485,8 @@ def _spline(dx, mode):
             )
         else:
             raise NotImplementedError(
-                f"The mode {mode} is invalid, please choose bilinear, " +
-                "bicubic or schaum."
+                f"The mode {mode} is invalid, please choose bilinear, "
+                + "bicubic or schaum."
             )
 
 
diff --git a/spyrit/test/test_core_recon.py b/spyrit/test/test_core_recon.py
index 280a4883..0eb3430a 100644
--- a/spyrit/test/test_core_recon.py
+++ b/spyrit/test/test_core_recon.py
@@ -80,11 +80,11 @@ def rotate(t):
     # deformation field
     time_vector = torch.linspace(0.25, M // 4, M)
     field = AffineDeformationField(rotate, time_vector, (H, H))
-    img_motion = field(img, mode='bilinear')
+    img_motion = field(img, mode="bilinear")
     # measurement
     y = meas_op(img_motion)
     # build H_dyn and H_dyn_pinv
-    meas_op.build_H_dyn(field, 'bilinear')
+    meas_op.build_H_dyn(field, "bilinear")
     meas_op.build_H_dyn_pinv()
     # reconstruction
     recon_op = PseudoInverse()