Plotly:如何设置具有分组图例的多个子图？

import plotly.graph_objects as go
from plotly.subplots import make_subplots

fig = make_subplots(rows=2, cols=2)

fig.add_trace(go.Scatter(x=[1, 2, 3], y=[4, 5, 6], name='Trace 1'), row=1, col=1)
fig.add_trace(go.Scatter(x=[1, 2, 3], y=[7, 8, 9], name='Trace 2'), row=1, col=2)
fig.add_trace(go.Scatter(x=[1, 2, 3], y=[10, 11, 12], name='Trace 3'), row=2, col=1)
fig.add_trace(go.Scatter(x=[1, 2, 3], y=[13, 14, 15], name='Trace 4'), row=2, col=2)

fig.update_layout(showlegend=True, legend=dict(x=0, y=1))

fig.show()