code: def snip(tag="",start=-2,write_date=True):
      
      import IPython
      i = IPython.get_ipython()
      last_history = i.history_manager.get_range(start=start,stop=start+1,output=True)
      with open("ipython_history.py",'a') as output_file:
          for l in last_history:
              global _session_description
              output_file.write('\n\n\n'+('#'*80)+'\n')
              if _session_description != "":
                  output_file.write('#\n'+_lines_as_comments(_session_description)+'\n#\n')
              if tag != "":
                  output_file.write(_lines_as_comments(tag)+'\n')
              if write_date:
                  import datetime
                  output_file.write('# '+datetime.datetime.now().isoformat()+'\n')
              output_file.write('\n\n# In ['+str(l[1])+']:\n'+l[2][0])
              _last_inputs.append(l[2][0])
              _tagged_inputs[tag] = _tagged_inputs.get(tag,[])
              _tagged_inputs[tag].append(l[2][0])
              output_file.write('\n\n# Out ['+str(l[1])+']:\n'+_lines_as_comments(repr(l[2][1])))
docs: This function records a previously execute notebook cell into a file (default: ipython_history.py)
  
          a tag can be added to sort the cell
  
          `start` defines which cell in the history to record. Default is -2, ie. the one executed previously to the current one.