def narrow_row(x, start, stop):
    """Narrow down the tensor along the first dimension.

    Parameters
    ----------
    x : Tensor
        The input tensor.
    start : int
        The start index (inclusive).
    stop : int
        The stop index (exclusive).

    Returns
    -------
    Tensor
        The narrowed tensor

    Notes
    -----
    The returned tensor could be a view of the original tensor.
    """
    pass
