def list_elbv2_attached_secgroups(elbv2) -> list:
    """
    List security groups attached to Elastic Load Balancers V2
    """
    elbv2_attached_groups = []
    boto_load_balancers = elbv2.describe_load_balancers()
    for elbv2_obj in boto_load_balancers['LoadBalancers']:
        if 'SecurityGroups' in elbv2_obj:
            for security_group in elbv2_obj['SecurityGroups']:
                elbv2_attached_groups.append(
                    security_group
                )
    return elbv2_attached_groups