title: overlap plots in matplotlib
body: <p>I am plotting year-month <code>periodIndex</code> as x, and variable as y. I have the following function to produce the plot:</p>
  
  <pre><code>def visualize_ilf(pandas_df):
      import seaborn as sns
      import matplotlib.pyplot as plt
      plt.rcParams["figure.figsize"] = (30,9)
      pandas_df['idx'] = pandas_df.index # is monthly
      ax1 = pandas_df.plot(x='idx', y='dep_score')
      ax2 = pandas_df.plot(x='idx', y='message_counts')
      ax3 = pandas_df.plot(x='idx', y='hasQuestionMark_INT')
      ax4 = pandas_df.plot(x='idx', y='sharing_ind')
      return plt.show()
  </code></pre>
  
  <p>This works fine, but I get separate plots for each y. How can I overlap the plots?</p>