code: def code_to_text(self):
          
          source = copy(self.source)
          comment_magic(source, self.language, self.comment_magics)
  
          options = []
          if self.cell_type == 'code' and self.language:
              options.append(self.language)
  
          filtered_metadata = {key: self.metadata[key] for key in self.metadata
                               if key not in ['active', 'language']}
  
          if filtered_metadata:
              options.append(metadata_to_md_options(filtered_metadata))
  
          return ['```{}'.format(' '.join(options))] + source + ['```']
docs: Return the text representation of a code cell