code: def apply_security_groups(self, security_groups):
          
          if isinstance(security_groups, str) or \
                isinstance(security_groups, unicode):
              security_groups = [security_groups]
          new_sgs = self.connection.apply_security_groups_to_lb(
                                           self.name, security_groups)
          self.security_groups = new_sgs
docs: Applies security groups to the load balancer.
          Applying security groups that are already registered with the 
          Load Balancer has no effect.
  
          :type security_groups: string or List of strings
          :param security_groups: The name of the security group(s) to add.