new_contents: import matplotlib
  import matplotlib.pyplot as plt
  
  import figplotter
  
  from figplotter.utils import Parameter as P
  from figplotter.plot import figure, cluster_series
  
  def figure_simple_cluster():
      fig = figure()
      ax = fig.add_subplot(111)
      read  = [1, 2,   4,    5]
      write = [2, 3, 3.5, 3.75]
  
      clusters = [ 'local', 'remote', 'copy', 'peak' ]
      series = {}
      for i, cluster in enumerate(clusters):
          series[cluster] = {}
  
          series[cluster]['Read']  = read[i]
          series[cluster]['Write'] = write[i]
  
      cluster_series(ax,
                     series,
                     clusters,
                     bar_params = {
                         'color' : P({
                             'Read': 'b',
                             'Write': 'g',
                         })
                     })
      fig.show()
  
  figure_simple_cluster()
  
  plt.show()
  
subject: Add a new test file for clustering. Add simple clustering example.