code: def _do_eval(self, cmd, args):
          
          code = args[0].lstrip()
          if not code:
              self.stderr.write('e: cannot evalutate empty expression\n')
              return
          try:
              eval(code)
          except:
              self.stderr.write('''When executing code '{}', the following error was raised:\n\n'''.format(code))
              self.stderr.write(textwrap.indent(traceback.format_exc(), '    '))
docs: \
          Evaluate python code.
              e <expr>        Evaluate <expr>.