The `keepdims` option is not enforced in fonction `numpy.ma.amax`: ``` python >>> import numpy >>> x = numpy.random.randn(4, 3) >>> numpy.amax(x, axis=-1, keepdims=True).shape (4, 1) >>> numpy.ma.amax(numpy.ma.masked_array(x), axis=-1, keepdims=True).shape (4,) ```