anchor.diff:  deftask plot( png( File ) : cls( File ) k )in python *{
   
   import numpy as np
  +import matplotlib as mpl
  +mpl.use('Agg')
   import matplotlib.pyplot as plt
   
   clusters = np.load( cls ).item()
  
positive.code: 
  plt = plot( cls: cls, k: k );
  
  plt;
negative.code: deftask gen_data( data( File ) : N k ) in python *{
  
  import numpy as np
  import random
  
  random.seed( 42 )
  
  N = int( N )
  k = int( k )
  