docs: def execute(self):
          """Convert the notebook to a python script and execute it, returning the local context
          as a dict"""
  
          from nbformat import read
          from nbconvert.exporters import export_script
          from cStringIO import StringIO
  
          notebook = read(StringIO(self.record.unpacked_contents), 4)
  
          script, resources = export_script(notebook)
  
          env_dict = {}
  
          exec (compile(script.replace('# coding: utf-8', ''), 'script', 'exec'), env_dict)
  
          return env_dict