code: def open(self):
          
          device_type = 'cisco_ios'
          if self.transport == 'telnet':
              device_type = 'cisco_ios_telnet'
          self.device = ConnectHandler(device_type=device_type,
                                       host=self.hostname,
                                       username=self.username,
                                       password=self.password,
                                       **self.netmiko_optional_args)
          # ensure in enable mode
          self.device.enable()
docs: Open a connection to the device.