Flatten figures of subplot for easy plotting

I just dabbled into plotly for some project and i noticed via the documentation and stackoverflow that plotly does not have an easy way to flatten figures for easy subplotting. You literally have to explicitly define which rows and column you want your trace to be. It would be great if plotly could have a similar feature to matplotlib where you could flatten a series of axes subplots into a list and just for loop through it. Example below for clarity:

fig, axs = plt.subplots(nrows=4,ncols=4)
axs = axs.flatten()
for ax in axs:
    ax.plot() # plot on each subplot from left to right for each row

首先查看 subplot 文档以及 plotly.py 中现有的 figure 和 subplot API；该 issue 未指定具体的文件或测试。确定 flattening 接口将如何为迭代映射 subplot 位置，并在用户可以按 row-major 顺序迭代 subplot、而无需显式选择每一行和每一列时，视为工作完成。