title: How to change the plot line color from blue to black?
body: <p>I am stuck when I have generated a set of data and tried to color the plot line in python. </p>
  
  <p>For example I would like to change the line color from blue to black here.</p>
  
  <p>This is what I have and returns is the set of data that I got from pandas.</p>
  
  <pre><code>ax=plt.gca()
  ax.set_axis_bgcolor('#cccccc')
  returns.plot()
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/k36d1.png" alt="Screenshot of plot"></p>