new_contents: from pybel import *
  from zlib import compress, decompress
  import copy_reg
  
  ### Monkeypatch pybel objects pickling
  # default pickle format - mol2 as the most comrahensive common one
  pickle_format = 'mol2'
  def pickle_mol(self):
      return unpickle_mol, (self.write(pickle_format),)
  
  def unpickle_mol(string):
      return readstring(pickle_format, string)
  copy_reg.pickle(Molecule, pickle_mol, unpickle_mol)
  
subject: Introduce pickling to pybel