'Add a trace to your figure bound to axes at the row, col index.
The row, col index is generated from figures created with
plotly.tools.make_subplots and can be viewed with
Figure.print_grid.
:param (dict) trace: The data trace to be bound.
:param (int) row: Subplot row index (see Figure.print_grid).
:param (int) col: Subplot column index (see Figure.print_grid).
Example:
# stack two subplots vertically
fig = tools.make_subplots(rows=2)
This is the format of your plot grid:
[ (1,1) x1,y1 ]
[ (2,1) x2,y2 ]
fig.append_trace(Scatter(x=[1,2,3], y=[2,1,2]), 1, 1)
fig.append_trace(Scatter(x=[1,2,3], y=[2,1,2]), 2, 1)'

def append_trace(self, trace, row, col):

    try:
        grid_ref = self._grid_ref
    except AttributeError:
        raise Exception('In    order    to    use    Figure.append_trace,    you    must    first    use    plotly.tools.make_subplots    to    create    a    subplot    grid.')
    if (row <= 0):
        raise Exception('Row    value    is    out    of    range.    Note:    the    starting    cell    is    (1,    1)')
    if (col <= 0):
        raise Exception('Col    value    is    out    of    range.    Note:    the    starting    cell    is    (1,    1)')
    try:
        ref = grid_ref[(row - 1)][(col - 1)]
    except IndexError:
        raise Exception('The    (row,    col)    pair    sent    is    out    of    range.    Use    Figure.print_grid    to    view    the    subplot    grid.    ')
    if ('scene' in ref[0]):
        trace['scene'] = ref[0]
        if (ref[0] not in self['layout']):
            raise Exception('Something    went    wrong.    The    scene    object    for    ({r},{c})    subplot    cell    got    deleted.'.format(r=row, c=col))
    else:
        xaxis_key = 'xaxis{ref}'.format(ref=ref[0][1:])
        yaxis_key = 'yaxis{ref}'.format(ref=ref[1][1:])
        if ((xaxis_key not in self['layout']) or (yaxis_key not in self['layout'])):
            raise Exception('Something    went    wrong.    An    axis    object    for    ({r},{c})    subplot    cell    got    deleted.'.format(r=row, c=col))
        trace['xaxis'] = ref[0]
        trace['yaxis'] = ref[1]
    self['data'] += [trace]
