Function plot_accuracy_vs_round_number

Plots the clients' average test accuracy vs. the round number. Args: stat_metrics: pd.DataFrame as written by writer.py. weighted: Whether the average across clients should be weighted by number of test samples. plot_stds: Whether to plot error bars correspon

(stat_metrics, weighted=False, plot_stds=False,
        figsize=(10, 8), title_fontsize=16, **kwargs)