code: def command(self, command, capture=True):
          
          if capture:
              self.command('redir! >> {0}'.format(self._tempfile.name), False)
          self.set_mode('command')
          self.send_keys('{0}\n'.format(command))
          if capture:
              self.command('redir END', False)
              return self._tempfile.read().strip('\n')
docs: Execute command on *Vim*.
          .. warning:: Do not use ``redir`` command if ``capture`` is ``True``.
          It's already enabled for internal use.
  
          If ``capture`` argument is set ``False``,
          the command execution becomes slightly faster.
  
          Example:
  
          >>> import headlessvim
          >>> with headlessvim.open() as vim:
          ...     vim.command('echo 0')
          ...
          '0'
          >>> with headlessvim.open() as vim:
          ...     vim.command('let g:spam = "ham"', False)
          ...     vim.echo('g:spam')
          ...
          'ham'
  
          :param string command: a command to execute
          :param boolean capture: ``True`` if command's output needs to be
                                  captured, else ``False``
          :return: the output of the given command
          :rtype: string