Add missing docstring to is_gray.

bdice · bdice · commit c7115f04ca54 · 2020-08-08T22:47:20.000-05:00
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -677,6 +677,7 @@ def _init(self):
         raise NotImplementedError("Abstract class only")
 
     def is_gray(self):
+        """Determine if the color map is grayscale."""
         if not self._isinit:
             self._init()
         return (np.all(self._lut[:, 0] == self._lut[:, 1]) and
