title: matplotlib: change stem plot linewidth
body: <p>i have image containing 4 subplots:</p>
  
  <pre><code>    #!/usr/bin/env python3
      import matplotlib.pyplot as plt
      f, axarr = plt.subplots(2, 2) 
      axarr[0,1].stem([1,3,-4],linefmt='b-', markerfmt='bs', basefmt='k-')
      plt.show()
  </code></pre>
  
  <p>I want to change the linewidth of one plot (stem plot). Is there an easy way to do this?</p>