message: docs: fix typo in keras' convolutional.py
diff: @@ -2492,7 +2492,7 @@ class Cropping3D(Layer):
  """Cropping layer for 3D data (e.g. spatial or spatio-temporal).
  Arguments:
  - cropping: Int, or tuple of 23ints, or tuple of 3 tuples of 2 ints.
  + cropping: Int, or tuple of 3 ints, or tuple of 3 tuples of 2 ints.
  - If int: the same symmetric cropping
  is applied to depth, height, and width.
  - If tuple of 3 ints: interpreted as two different
  