title: Plotting shap plots in 2x2 grid
body: <p>I am trying to plot 4 Shap dependency plots in 2x2 subplots but cannot get it to work. I have tried the following:</p>
  <pre><code>fig, axes = plt.subplots(nrows=2, ncols=2, figsize=(10,10))
  ax1 = plt.subplot(221)
  shap.dependence_plot('age', shap_values[1], X_train, ax=ax1)
  ax2 = plt.subplot(222)
  shap.dependence_plot('income', shap_values[1], X_train, ax=ax2)
  ax3 = plt.subplot(223)
  shap.dependence_plot('score', shap_values[1], X_train, ax=ax2)
  </code></pre>
  <p>And this:</p>
  <pre><code>plt.figure(figsize=(10,5))
  plt.subplot(1,2,1)
  shap.dependence_plot('age', shap_values[1], X_train)
  plt.subplot(1,2,2)
  shap.dependence_plot('income', shap_values[1], X_train)
  plt.subplot(2,2,3)
  shap.dependence_plot('score', shap_values[1], X_train)
  plt.tight_layout()
  plt.show()
  </code></pre>
  <p>It keeps plotting them on different rows, instead of a 2x2 format.</p>