def hstack(blocks, format=None, dtype=None):
    """
    Stack sparse matrices horizontally (column wise).

    This wrap the method hstack from scipy.

    Parameters
    ----------
    blocks
        List of sparse array of compatible shape.
    format
        String representing the output format. Default is csc.
    dtype
        Output dtype.

    Returns
    -------
    array
        The concatenation of the sparse array column wise.

    Notes
    -----
    The number of line of the sparse matrix must agree.

    The grad implemented is regular, i.e. not structured.

    """

    blocks = [as_sparse_variable(i) for i in blocks]
    if dtype is not None:
        dtype = theano.scalar.upcast(*[i.dtype for i in blocks])
    return HStack(format=format, dtype=dtype)(*blocks)
dataset/ETHPy150Open rizar/attention-lvcsr/libs/Theano/theano/sparse/basic.py/hstack/operator `is` -> `is not`