title: Set Python to custom-set y-axis minor tick mark frequency
body: <p>This question is related to plotting minor tick mars on the y-axis in a Python plot with
  matplotlib.</p>
  
  <p>Here is the code that I have:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  from matplotlib.ticker import MultipleLocator
  
  fig, ax = plt.subplots()
  fig.set_facecolor('white')
  
  x = [1,2,3]
  plt.subplot(211)
  plt.plot([1,2,3], label="test1")
  plt.plot([3,2,1], label="test2")
  plt.xticks()
  plt.yticks()
  ax.yaxis.set_minor_locator(MultipleLocator(5))
  plt.show()
  </code></pre>
  
  <p>When I generate this plot, I am not getting any minor tick marks.</p>
  
  <p>I have attached here the plot that this code gives me.
  <img src="https://i.stack.imgur.com/W8NHa.png" alt="enter image description here"></p>
  
  <p>Is it possible for me to display the minor tick marks for the y-axis here?</p>