title: matplotlib: plot multiple columns of pandas data frame on the bar chart
body: <p>I am using the following code to plot a bar-chart:</p>
  
  <pre><code>import matplotlib.pyplot as pls 
  my_df.plot(x='my_timestampe', y='col_A', kind='bar') 
  plt.show()
  </code></pre>
  
  <p>The plot works fine. However, I want to improve the graph by having 3 columns: 'col_A', 'col_B', and 'col_C' all on the plot. Like in the example figure below:</p>
  
  <p><a href="https://i.stack.imgur.com/34kIU.png" rel="noreferrer"><img src="https://i.stack.imgur.com/34kIU.png" alt="enter image description here"></a></p>
  
  <p>I would like the <code>col_A</code> displayed in blue above x-axis, <code>col_B</code> in red below x-axis, and <code>col_C</code> in green above x-axis. Is this something possible in matplotlib? How do I make changes to plot all the three columns? Thanks!</p>