def METHOD_NAME(m, k=0, gpu=None):
    """
    Upper triangle of a tensor.
    Return a copy of a matrix with the elements below the `k`-th diagonal
    zeroed.
    Please refer to the documentation for `tril` for further details.
    See Also
    --------
    tril : lower triangle of a tensor
    Examples
    --------
    >>> import mars.tensor as mt
    >>> mt.triu([[1,2,3],[4,5,6],[7,8,9],[10,11,12]], -1).execute()
    array([[ 1,  2,  3],
           [ 4,  5,  6],
           [ 0,  8,  9],
           [ 0,  0, 12]])
    """
    m = astensor(m)
    gpu = m.op.gpu if gpu is None else gpu
    op = TensorTriu(k, dtype=m.dtype, sparse=m.issparse(), gpu=gpu)
    return op(m)