使用seaborn绘制多个多绘图面板

我试图在一个图形中绘制三个面板（共三个），但我得到的只是一个空网格和三个内部面板。我做错了什么？

def plot_qc_metrics(adata, key):
    
    pg.qc_metrics(adata, min_genes=100,  mito_prefix='MT-')
    pg.filter_data(adata)

    fig, ax = plt.subplots(1, 3, figsize=(15, 5), sharey=True)
    fig.suptitle(key, fontsize=16)

    sns.histplot(data = adata.obs, x = 'n_counts',  bins=50, log_scale=True, ax=ax[0])
    ax[0].set(xlim=(1, 100000), xlabel='log nUMI')

    data = adata.obs['n_genes']
    sns.histplot(data = adata.obs, x = 'n_genes',  bins=50, log_scale=True, ax=ax[1])
    ax[1].set(xlim=(1, 100000), xlabel='log nGenes')

    data = np.log2(adata.obs['percent_mito'])
    sns.histplot(data = data, x=data,  bins=100, ax=ax[2])
    # ax[2].set(xlim=(np.min(data), np.max(data)), xlabel='log2(percent_mito)')
    ax[2].xaxis.set_major_formatter(ticker.FuncFormatter(lambda x, pos: '$2^{%.0f}$' % x))

    return fig, ax

    adata_dict = {
        'org_1': org_1, 
        'org_2': org_2, 
        'org_3': org_3
    }
    
    fig, ax = plt.subplots(nrows = 3, ncols = len(adata_dict), figsize=(15, 5), sharey=True)
    
    for i, (key, adata) in enumerate(adata_dict.items()):
        subfig, subax = plot_qc_metrics(adata, key)
        ax[i] = subax
    
    plt.tight_layout()
    plt.show()