Document prepare_data.

anntzer · anntzer · commit babb03eaaee4 · 2015-11-12T09:35:47.000-08:00
diff --git a/lib/matplotlib/backends/qt_editor/figureoptions.py b/lib/matplotlib/backends/qt_editor/figureoptions.py
@@ -81,6 +81,15 @@ def figure_edit(axes, parent=None):
 
         def prepare_data(d, init):
             """Prepare entry for FormLayout.
+
+            `d` is a mapping of values to representations (a single value may
+            have multiple representations, in particular the marker styles
+            `None`, `"None"`, `"none"` and `""` are synonyms); `init` is one
+            representation of the initial value.
+
+            This function returns an list suitable for initializing a
+            FormLayout combobox, namely `[initial_representation, (value,
+            representation), (value, representation), ...]`.
             """
             # List items in dict, dropping duplicate values, sorting by values.
             kvs = [(k, v) for v, k in
