new_contents: import difflib
  
  def diff(a, b):
  	sm = difflib.SequenceMatcher(a, b)
  	out = []
  	for opcode, a0, a1, b0, b1 in sm.get_opcodes():
  		if opcode == "equal":
  			output.append(seqm.a[a0:a1])
  		elif opcode == "insert":
  			output.append("\x1f" + seqm.b[b0:b1] + "\x1f")
  		elif opcode == "delete":
  			pass
  		elif opcode == "replace":
  			raise NotImplementedError("encountered 'replace' opcode")
  		else:
  			raise RuntimeError("unknown opcode")
  	return "".join(out)
  
  
subject: add diff library for module/romaji