# Buggy code
def main():
    argument_spec = ec2_argument_spec()
    argument_spec.update(
        dict(
            dhcp_options_id=dict(type="str", default=None),
            domain_name=dict(type="str", default=None),
            dns_servers=dict(type="list", default=None),
            ntp_servers=dict(type="list", default=None),
            netbios_name_servers=dict(type="list", default=None),
            netbios_node_type=dict(type="int", default=None),
            vpc_id=dict(type="str", default=None),
            delete_old=dict(type="bool", default=True),
            inherit_existing=dict(type="bool", default=False),
            tags=dict(type="dict", default=None, aliases=["resource_tags"]),
            state=dict(type="str", default="present", choices=["present", "absent"]),
        )
    )

    module = AnsibleModule(argument_spec=argument_spec, supports_check_mode=True)
    params = module.params
    found = False
    changed = False
    new_options = collections.defaultdict(lambda: None)

    if not HAS_BOTO:
        module.fail_json(msg="boto is required for this module")

    region, ec2_url, boto_params = get_aws_connection_info(module)
    connection = connect_to_aws(boto.vpc, region, **boto_params)

    existing_options = None

    # First check if we were given a dhcp_options_id
    if not params["dhcp_options_id"]:
        # No, so create new_options from the parameters
        if params["dns_servers"] is not None:
            new_options["domain-name-servers"] = params["dns_servers"]
        if params["netbios_name_servers"] is not None:
            new_options["netbios-name-servers"] = params["netbios_name_servers"]
        if params["ntp_servers"] is not None:
            new_options["ntp-servers"] = params["ntp_servers"]
        if params["domain_name"] is not None:
            # needs to be a list for comparison with boto objects later
            new_options["domain-name"] = [params["domain_name"]]
        if params["netbios_node_type"] is not None:
            # needs to be a list for comparison with boto objects later
            new_options["netbios-node-type"] = [str(params["netbios_node_type"])]
        # If we were given a vpc_id then we need to look at the options on that
        if params["vpc_id"]:
            existing_options = fetch_dhcp_options_for_vpc(connection, params["vpc_id"])
            # if we've been asked to inherit existing options, do that now
            if params["inherit_existing"]:
                if existing_options:
                    for option in [
                        "domain-name-servers",
                        "netbios-name-servers",
                        "ntp-servers",
                        "domain-name",
                        "netbios-node-type",
                    ]:
                        if (
                            existing_options.options.get(option)
                            and new_options[option] != []
                            and (not new_options[option] or [""] == new_options[option])
                        ):
                            new_options[option] = existing_options.options.get(option)

            # Do the vpc's dhcp options already match what we're asked for? if so we are done
            if existing_options and new_options == existing_options.options:
                module.exit_json(
                    changed=changed,
                    new_options=new_options,
                    dhcp_options_id=existing_options.id,
                )

        # If no vpc_id was given, or the options don't match then look for an existing set using tags
        found, dhcp_option = match_dhcp_options(connection, params["tags"], new_options)

    # Now let's cover the case where there are existing options that we were told about by id
    # If a dhcp_options_id was supplied we don't look at options inside, just set tags (if given)
    else:
        supplied_options = connection.get_all_dhcp_options(
            filters={"dhcp-options-id": params["dhcp_options_id"]}
        )
        if len(supplied_options) != 1:
            if params["state"] != "absent":
                module.fail_json(
                    msg=" a dhcp_options_id was supplied, but does not exist"
                )
        else:
            found = True
            dhcp_option = supplied_options[0]
            if params["state"] != "absent" and params["tags"]:
                ensure_tags(
                    module,
                    connection,
                    dhcp_option.id,
                    params["tags"],
                    False,
                    module.check_mode,
                )

    # Now we have the dhcp options set, let's do the necessary

    # if we found options we were asked to remove then try to do so
    if params["state"] == "absent":
        if not module.check_mode:
            if found:
                changed = remove_dhcp_options_by_id(connection, dhcp_option.id)
        module.exit_json(changed=changed, new_options={})

    # otherwise if we haven't found the required options we have something to do
    elif not module.check_mode and not found:
        # create some dhcp options if we weren't able to use existing ones
        if not found:
            # Convert netbios-node-type and domain-name back to strings
            if new_options["netbios-node-type"]:
                new_options["netbios-node-type"] = new_options["netbios-node-type"][0]
            if new_options["domain-name"]:
                new_options["domain-name"] = new_options["domain-name"][0]

            # create the new dhcp options set requested
            dhcp_option = connection.create_dhcp_options(
                new_options["domain-name"],
                new_options["domain-name-servers"],
                new_options["ntp-servers"],
                new_options["netbios-name-servers"],
                new_options["netbios-node-type"],
            )
            changed = True
            if params["tags"]:
                ensure_tags(
                    module,
                    connection,
                    dhcp_option.id,
                    params["tags"],
                    False,
                    module.check_mode,
                )

    # If we were given a vpc_id, then attach the options we now have to that before we finish
    if params["vpc_id"] and not module.check_mode:
        changed = True
        connection.associate_dhcp_options(dhcp_option.id, params["vpc_id"])
        # and remove old ones if that was requested
        if params["delete_old"] and existing_options:
            remove_dhcp_options_by_id(connection, existing_options.id)

    module.exit_json(
        changed=changed, new_options=new_options, dhcp_options_id=dhcp_option.id
    )


# Traceback (boto.exception.EC2ResponseError)
Traceback (most recent call last):
File "/tmp/ansible_oqa3j78q/ansible_module_ec2_vpc_dhcp_option.py", line 233, in ensure_tags
vpc_conn.create_tags(resource_id, to_add, dry_run=check_mode)
File "/usr/local/lib/python3.6/dist-packages/boto/ec2/connection.py", line 4219, in create_tags
return self.get_status('CreateTags', params, verb='POST')
File "/usr/local/lib/python3.6/dist-packages/boto/connection.py", line 1227, in get_status
raise self.ResponseError(response.status, response.reason, body)
boto.exception.EC2ResponseError: EC2ResponseError: 400 Bad Request
<?xml version="1.0" encoding="UTF-8"?>
<Response><Errors><Error><Code>InvalidDhcpOptionsID.NotFound</Code><Message>The dhcpOptions ID 'dopt-6cf05914' does not exist</Message></Error></Errors><RequestID>d602f51a-66b5-445f-9b5b-38ffdbccda29</RequestID></Response>

# Fixed code
def main():
    argument_spec = ec2_argument_spec()
    argument_spec.update(
        dict(
            dhcp_options_id=dict(type="str", default=None),
            domain_name=dict(type="str", default=None),
            dns_servers=dict(type="list", default=None),
            ntp_servers=dict(type="list", default=None),
            netbios_name_servers=dict(type="list", default=None),
            netbios_node_type=dict(type="int", default=None),
            vpc_id=dict(type="str", default=None),
            delete_old=dict(type="bool", default=True),
            inherit_existing=dict(type="bool", default=False),
            tags=dict(type="dict", default=None, aliases=["resource_tags"]),
            state=dict(type="str", default="present", choices=["present", "absent"]),
        )
    )

    module = AnsibleModule(argument_spec=argument_spec, supports_check_mode=True)
    params = module.params
    found = False
    changed = False
    new_options = collections.defaultdict(lambda: None)

    if not HAS_BOTO:
        module.fail_json(msg="boto is required for this module")

    region, ec2_url, boto_params = get_aws_connection_info(module)
    connection = connect_to_aws(boto.vpc, region, **boto_params)

    existing_options = None

    # First check if we were given a dhcp_options_id
    if not params["dhcp_options_id"]:
        # No, so create new_options from the parameters
        if params["dns_servers"] is not None:
            new_options["domain-name-servers"] = params["dns_servers"]
        if params["netbios_name_servers"] is not None:
            new_options["netbios-name-servers"] = params["netbios_name_servers"]
        if params["ntp_servers"] is not None:
            new_options["ntp-servers"] = params["ntp_servers"]
        if params["domain_name"] is not None:
            # needs to be a list for comparison with boto objects later
            new_options["domain-name"] = [params["domain_name"]]
        if params["netbios_node_type"] is not None:
            # needs to be a list for comparison with boto objects later
            new_options["netbios-node-type"] = [str(params["netbios_node_type"])]
        # If we were given a vpc_id then we need to look at the options on that
        if params["vpc_id"]:
            existing_options = fetch_dhcp_options_for_vpc(connection, params["vpc_id"])
            # if we've been asked to inherit existing options, do that now
            if params["inherit_existing"]:
                if existing_options:
                    for option in [
                        "domain-name-servers",
                        "netbios-name-servers",
                        "ntp-servers",
                        "domain-name",
                        "netbios-node-type",
                    ]:
                        if (
                            existing_options.options.get(option)
                            and new_options[option] != []
                            and (not new_options[option] or [""] == new_options[option])
                        ):
                            new_options[option] = existing_options.options.get(option)

            # Do the vpc's dhcp options already match what we're asked for? if so we are done
            if existing_options and new_options == existing_options.options:
                module.exit_json(
                    changed=changed,
                    new_options=new_options,
                    dhcp_options_id=existing_options.id,
                )

        # If no vpc_id was given, or the options don't match then look for an existing set using tags
        found, dhcp_option = match_dhcp_options(connection, params["tags"], new_options)

    # Now let's cover the case where there are existing options that we were told about by id
    # If a dhcp_options_id was supplied we don't look at options inside, just set tags (if given)
    else:
        supplied_options = connection.get_all_dhcp_options(
            filters={"dhcp-options-id": params["dhcp_options_id"]}
        )
        if len(supplied_options) != 1:
            if params["state"] != "absent":
                module.fail_json(
                    msg=" a dhcp_options_id was supplied, but does not exist"
                )
        else:
            found = True
            dhcp_option = supplied_options[0]
            if params["state"] != "absent" and params["tags"]:
                ensure_tags(
                    module,
                    connection,
                    dhcp_option.id,
                    params["tags"],
                    False,
                    module.check_mode,
                )

    # Now we have the dhcp options set, let's do the necessary

    # if we found options we were asked to remove then try to do so
    if params["state"] == "absent":
        if not module.check_mode:
            if found:
                changed = remove_dhcp_options_by_id(connection, dhcp_option.id)
        module.exit_json(changed=changed, new_options={})

    # otherwise if we haven't found the required options we have something to do
    elif not module.check_mode and not found:
        # create some dhcp options if we weren't able to use existing ones
        if not found:
            # Convert netbios-node-type and domain-name back to strings
            if new_options["netbios-node-type"]:
                new_options["netbios-node-type"] = new_options["netbios-node-type"][0]
            if new_options["domain-name"]:
                new_options["domain-name"] = new_options["domain-name"][0]

            # create the new dhcp options set requested
            dhcp_option = connection.create_dhcp_options(
                new_options["domain-name"],
                new_options["domain-name-servers"],
                new_options["ntp-servers"],
                new_options["netbios-name-servers"],
                new_options["netbios-node-type"],
            )

            # wait for dhcp option to be accessible
            found_dhcp_opt = False
            start_time = time()
            while time() < start_time + 300:
                try:
                    found_dhcp_opt = connection.get_all_dhcp_options(
                        dhcp_options_ids=[dhcp_option.id]
                    )
                except EC2ResponseError as e:
                    if e.error_code == "InvalidDhcpOptionID.NotFound":
                        sleep(3)
                    else:
                        module.fail_json(
                            msg="Failed to describe DHCP options",
                            exception=traceback.format_exc,
                        )
                else:
                    break
            if not found_dhcp_opt:
                module.fail_json(
                    msg="Failed to wait for {0} to be available.".format(dhcp_option.id)
                )

            changed = True
            if params["tags"]:
                ensure_tags(
                    module,
                    connection,
                    dhcp_option.id,
                    params["tags"],
                    False,
                    module.check_mode,
                )

    # If we were given a vpc_id, then attach the options we now have to that before we finish
    if params["vpc_id"] and not module.check_mode:
        changed = True
        connection.associate_dhcp_options(dhcp_option.id, params["vpc_id"])
        # and remove old ones if that was requested
        if params["delete_old"] and existing_options:
            remove_dhcp_options_by_id(connection, existing_options.id)

    module.exit_json(
        changed=changed, new_options=new_options, dhcp_options_id=dhcp_option.id
    )