code: def set_symbol(self, symbol):
          
          if symbol == 'EtherSwitch router':
              symbol = 'multilayer_switch'
          elif symbol == 'Host':
              symbol = 'computer'
  
          normal = ':/symbols/%s.normal.svg' % symbol
          selected = ':/symbols/%s.selected.svg' % symbol
  
          self.node['default_symbol'] = normal
          self.node['hover_symbol'] = selected
docs: Set a symbol for a device
  
          :param str symbol: Symbol to use