code: def code_to_text(self):
          
          active = is_active(self.ext, self.metadata)
          source = copy(self.source)
          escape_code_start(source, self.ext, self.language)
  
          if active:
              comment_magic(source, self.language, self.comment_magics)
  
          if not active:
              source = ['# ' + line if line else '#' for line in source]
  
          lines = []
          if not is_active('R', self.metadata):
              self.metadata['eval'] = False
          options = metadata_to_rmd_options(None, self.metadata)
          if options:
              lines.append('#+ {}'.format(options))
          lines.extend(source)
          return lines
docs: Return the text representation of a code cell