diff --git a/dmriprep/utils/vectors.py b/dmriprep/utils/vectors.py
index 19ff10ff..61febfea 100644
--- a/dmriprep/utils/vectors.py
+++ b/dmriprep/utils/vectors.py
@@ -456,6 +456,10 @@ def _rasb_to_bvec_list(in_rasb):
     Returns
     -------
     List of b-vectors as floats.
+    
+    Returns
+    --------
+    list : each element is a b-vector
     """
     import numpy as np
 
@@ -480,4 +484,4 @@ def _rasb_to_bval_floats(in_rasb):
     import numpy as np
 
     ras_b_mat = np.genfromtxt(in_rasb, delimiter="\t")
-    return [float(bval) for bval in ras_b_mat[:, 3] if bval > 0]
\ No newline at end of file
+    return [float(bval) for bval in ras_b_mat[:, 3] if bval > 0]