# Buggy code
def get_target_from_rule(module, ec2, rule, name, group, groups, vpc_id):
    """
    Returns tuple of (group_id, ip) after validating rule params.

    rule: Dict describing a rule.
    name: Name of the security group being managed.
    groups: Dict of all available security groups.

    AWS accepts an ip range or a security group as target of a rule. This
    function validate the rule specification and return either a non-None
    group_id or a non-None ip range.
    """

    FOREIGN_SECURITY_GROUP_REGEX = "^(\S+)/(sg-\S+)/(\S+)"
    group_id = None
    group_name = None
    ip = None
    target_group_created = False
    if "group_id" in rule and "cidr_ip" in rule:
        module.fail_json(msg="Specify group_id OR cidr_ip, not both")
    elif "group_name" in rule and "cidr_ip" in rule:
        module.fail_json(msg="Specify group_name OR cidr_ip, not both")
    elif "group_id" in rule and "group_name" in rule:
        module.fail_json(msg="Specify group_id OR group_name, not both")
    elif "group_id" in rule and re.match(
        FOREIGN_SECURITY_GROUP_REGEX, rule["group_id"]
    ):
        # this is a foreign Security Group. Since you can't fetch it you must create an instance of it
        owner_id, group_id, group_name = re.match(
            FOREIGN_SECURITY_GROUP_REGEX, rule["group_id"]
        ).groups()
        group_instance = SecurityGroup(owner_id=owner_id, name=group_name, id=group_id)
        groups[group_id] = group_instance
        groups[group_name] = group_instance
    elif "group_id" in rule:
        group_id = rule["group_id"]
    elif "group_name" in rule:
        group_name = rule["group_name"]
        if group_name == name:
            group_id = group.id
            groups[group_id] = group
            groups[group_name] = group
        elif group_name in groups and (
            vpc_id is None or groups[group_name].vpc_id == vpc_id
        ):
            group_id = groups[group_name].id
        else:
            if not rule.get("group_desc", "").strip():
                module.fail_json(
                    msg="group %s will be automatically created by rule %s and no description was provided"
                    % (group_name, rule)
                )
            if not module.check_mode:
                auto_group = ec2.create_security_group(
                    group_name, rule["group_desc"], vpc_id=vpc_id
                )
                group_id = auto_group.id
                groups[group_id] = auto_group
                groups[group_name] = auto_group
            target_group_created = True
    elif "cidr_ip" in rule:
        ip = rule["cidr_ip"]

    return group_id, ip, target_group_created


# Traceback (TypeError)
The full traceback is:
Traceback (most recent call last):
File "/var/folders/9w/w2f_52y12pq86rn0glnxdgs40000gn/T/ansible_QMC0WD/ansible_module_ec2_group.py", line 632, in <module>
main()
File "/var/folders/9w/w2f_52y12pq86rn0glnxdgs40000gn/T/ansible_QMC0WD/ansible_module_ec2_group.py", line 505, in main
group_id, ip, target_group_created = get_target_from_rule(module, ec2, rule, name, group, groups, vpc_id)
File "/var/folders/9w/w2f_52y12pq86rn0glnxdgs40000gn/T/ansible_QMC0WD/ansible_module_ec2_group.py", line 280, in get_target_from_rule
elif 'group_id' in rule and 'group_id' is not None and re.match(FOREIGN_SECURITY_GROUP_REGEX, rule['group_id']):
File "/usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/re.py", line 141, in match
return _compile(pattern, flags).match(string)
TypeError: expected string or buffer

fatal: [localhost]: FAILED! => {
"changed": false,
"failed": true,
"module_stderr": "Traceback (most recent call last):\n  File \"/var/folders/9w/w2f_52y12pq86rn0glnxdgs40000gn/T/ansible_QMC0WD/ansible_module_ec2_group.py\", line 632, in <module>\n    main()\n  File \"/var/folders/9w/w2f_52y12pq86rn0glnxdgs40000gn/T/ansible_QMC0WD/ansible_module_ec2_group.py\", line 505, in main\n    group_id, ip, tar
get_group_created = get_target_from_rule(module, ec2, rule, name, group, groups, vpc_id)\n  File \"/var/folders/9w/w2f_52y12pq86rn0glnxdgs40000gn/T/ansible_QMC0WD/ansible_module_ec2_group.py\", line 280, in get_target_from_rule\n    elif 'group_id' in rule and 'group_id' is not None and re.match(FOREIGN_SECURITY_GROUP_REGEX, rule['group_id
']):\n  File \"/usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/re.py\", line 141, in match\n    return _compile(pattern, flags).match(string)\nTypeError: expected string or buffer\n",
"module_stdout": "",
"msg": "MODULE FAILURE",
"rc": 1
}

# Fixed code
def get_target_from_rule(module, ec2, rule, name, group, groups, vpc_id):
    """
    Returns tuple of (group_id, ip) after validating rule params.

    rule: Dict describing a rule.
    name: Name of the security group being managed.
    groups: Dict of all available security groups.

    AWS accepts an ip range or a security group as target of a rule. This
    function validate the rule specification and return either a non-None
    group_id or a non-None ip range.
    """

    FOREIGN_SECURITY_GROUP_REGEX = "^(\S+)/(sg-\S+)/(\S+)"
    group_id = None
    group_name = None
    ip = None
    target_group_created = False
    if "group_id" in rule and "cidr_ip" in rule:
        module.fail_json(msg="Specify group_id OR cidr_ip, not both")
    elif "group_name" in rule and "cidr_ip" in rule:
        module.fail_json(msg="Specify group_name OR cidr_ip, not both")
    elif "group_id" in rule and "group_name" in rule:
        module.fail_json(msg="Specify group_id OR group_name, not both")
    elif rule.get("group_id") and re.match(
        FOREIGN_SECURITY_GROUP_REGEX, rule["group_id"]
    ):
        # this is a foreign Security Group. Since you can't fetch it you must create an instance of it
        owner_id, group_id, group_name = re.match(
            FOREIGN_SECURITY_GROUP_REGEX, rule["group_id"]
        ).groups()
        group_instance = SecurityGroup(owner_id=owner_id, name=group_name, id=group_id)
        groups[group_id] = group_instance
        groups[group_name] = group_instance
    elif "group_id" in rule:
        group_id = rule["group_id"]
    elif "group_name" in rule:
        group_name = rule["group_name"]
        if group_name == name:
            group_id = group.id
            groups[group_id] = group
            groups[group_name] = group
        elif group_name in groups and (
            vpc_id is None or groups[group_name].vpc_id == vpc_id
        ):
            group_id = groups[group_name].id
        else:
            if not rule.get("group_desc", "").strip():
                module.fail_json(
                    msg="group %s will be automatically created by rule %s and no description was provided"
                    % (group_name, rule)
                )
            if not module.check_mode:
                auto_group = ec2.create_security_group(
                    group_name, rule["group_desc"], vpc_id=vpc_id
                )
                group_id = auto_group.id
                groups[group_id] = auto_group
                groups[group_name] = auto_group
            target_group_created = True
    elif "cidr_ip" in rule:
        ip = rule["cidr_ip"]

    return group_id, ip, target_group_created