DOC: add a bit more comments

jklymak · jklymak · commit e2da0f96f22b · 2022-05-06T21:10:20.000Z
diff --git a/lib/matplotlib/cbook/__init__.py b/lib/matplotlib/cbook/__init__.py
@@ -1333,6 +1333,9 @@ def _check_1d(x):
     """Convert scalars to 1D arrays; pass-through arrays as is."""
     # Unpack in case of e.g. Pandas or xarray object
     x = _unpack_to_numpy(x)
+    # plot requires `shape` and `ndim`.  If passed an
+    # object that doesn't provide them, then force to numpy array.
+    # Note this will strip unit information.
     if (not hasattr(x, 'shape') or
             not hasattr(x, 'ndim') or
             len(x.shape) < 1):
