Clarify docs for stackplot.

QuLogic · QuLogic · commit 439b2c04d9ca · 2021-04-21T20:23:53.000-04:00
Fixes #20036.
diff --git a/lib/matplotlib/stackplot.py b/lib/matplotlib/stackplot.py
@@ -41,12 +41,17 @@ def stackplot(axes, x, *args,
           size of each layer. It is also called 'Streamgraph'-layout. More
           details can be found at http://leebyron.com/streamgraph/.
 
-    labels : Length N list of str
-        Labels to assign to each data series.
+    labels : list of str, optional
+        A sequence of labels to assign to each data series. If unspecified,
+        then no labels will be applied to artists.
 
-    colors : Length N list of color
-        A list or tuple of colors. These will be cycled through and used to
-        colour the stacked areas.
+    colors : list of color, optional
+        A sequence of colors to be cycled through and used to color the stacked
+        areas. The sequence need not be exactly the same length as the number
+        of provided *y*, in which case the colors will repeat from the
+        beginning.
+
+        If not specified, the colors from the Axes property cycle will be used.
 
     **kwargs
         All other keyword arguments are passed to `.Axes.fill_between`.
