diff --git a/specreduce/background.py b/specreduce/background.py
index df7c552..04a1d77 100644
--- a/specreduce/background.py
+++ b/specreduce/background.py
@@ -32,7 +32,7 @@ class Background(_ImageParser):
     ----------
     image : `~astropy.nddata.NDData`-like or array-like
         image with 2-D spectral image data
-    traces : List, `tracing.Trace`, int, float
+    traces : trace, int, float (single or list)
         Individual or list of trace object(s) (or integers/floats to define
         FlatTraces) to extract the background. If None, a `FlatTrace` at the
         center of the image (according to `disp_axis`) will be used.