new_contents: from sklearn.preprocessing import PolynomialFeatures
  from sklearn.decomposition import PCA
  import numpy as np
  
  X = np.arange(9).reshape(3, 3)
  print X
  
  poly = PolynomialFeatures(2)
  print poly.fit_transform(X)
  
  poly = PolynomialFeatures(interaction_only=True)
  print poly.fit_transform(X)
  
  pca = PCA(n_components=1)
  
  print pca.fit_transform(X)
  
subject: Add snippet with code to generate new features