# Buggy code
def main():
    argument_spec = ec2_argument_spec()
    argument_spec.update(
        dict(
            group_family=dict(
                type="str", choices=["memcached1.4", "redis2.6", "redis2.8", "redis3.2"]
            ),
            name=dict(required=True, type="str"),
            description=dict(type="str"),
            state=dict(required=True),
            values=dict(type="dict"),
        )
    )
    module = AnsibleModule(argument_spec=argument_spec)

    if not HAS_BOTO3:
        module.fail_json(msg="boto required for this module")

    parameter_group_family = module.params.get("group_family")
    parameter_group_name = module.params.get("name")
    group_description = module.params.get("description")
    state = module.params.get("state")
    values = module.params.get("values")

    # Retrieve any AWS settings from the environment.
    region, ec2_url, aws_connect_kwargs = get_aws_connection_info(module, boto3=True)
    if not region:
        module.fail_json(
            msg="Either region or AWS_REGION or EC2_REGION environment variable or boto config aws_region or ec2_region must be set."
        )

    connection = boto3_conn(
        module,
        conn_type="client",
        resource="elasticache",
        region=region,
        endpoint=ec2_url,
        **aws_connect_kwargs,
    )

    exists = get_info(connection, parameter_group_name)

    # check that the needed requirements are available
    if state == "present" and not (
        exists and parameter_group_family and group_description
    ):
        module.fail_json(
            msg="Creating a group requires a family group and a description."
        )
    elif state == "reset" and not exists:
        module.fail_json(
            msg="No group %s to reset. Please create the group before using the state 'reset'."
            % parameter_group_name
        )

    # Taking action
    changed = False
    if state == "present":
        if exists:
            # confirm that the group exists without any actions
            if not values:
                response = exists
                changed = False
            # modify existing group
            else:
                modifiable_params = make_current_modifiable_param_dict(
                    module, connection, parameter_group_name
                )
                changed = check_valid_modification(module, values, modifiable_params)
                response = modify(module, connection, parameter_group_name, values)
        # create group
        else:
            response, changed = create(
                module,
                connection,
                parameter_group_name,
                parameter_group_family,
                group_description,
            )
            if values:
                modifiable_params = make_current_modifiable_param_dict(
                    module, connection, parameter_group_name
                )
                changed = check_valid_modification(module, values, modifiable_params)
                response = modify(module, connection, parameter_group_name, values)
    elif state == "absent":
        if exists:
            # delete group
            response, changed = delete(module, connection, parameter_group_name)
        else:
            response = {}
            changed = False
    elif state == "reset":
        response, changed = reset(module, connection, parameter_group_name, values)

    facts_result = dict(changed=changed, elasticache=camel_dict_to_snake_dict(response))

    module.exit_json(**facts_result)


# Traceback (KeyError)
The full traceback is:
Traceback (most recent call last):
File "/tmp/ansible_wAJvSx/ansible_module_elasticache_parameter_group.py", line 330, in <module>
main()
File "/tmp/ansible_wAJvSx/ansible_module_elasticache_parameter_group.py", line 305, in main
modifiable_params = make_current_modifiable_param_dict(module, connection, parameter_group_name)
File "/tmp/ansible_wAJvSx/ansible_module_elasticache_parameter_group.py", line 156, in make_current_modifiable_param_dict
modifiable_params[param["ParameterName"]] = [param["AllowedValues"], param["DataType"], param["ParameterValue"]]
KeyError: 'AllowedValues'

fatal: [localhost]: FAILED! => {
"changed": false,
"failed": true,
"module_stderr": "Traceback (most recent call last):\n  File \"/tmp/ansible_wAJvSx/ansible_module_elasticache_parameter_group.py\", line 330, in <module>\n    main()\n  File \"/tmp/ansible_wAJvSx/ansible_module_elasticache_parameter_group.py\", line 305, in main\n    modifiable_params = make_current_modifiable_param_dict(module, connection, parameter_group_name)\n  File \"/tmp/ansible_wAJvSx/ansible_module_elasticache_parameter_group.py\", line 156, in make_current_modifiable_param_dict\n    modifiable_params[param[\"ParameterName\"]] = [param[\"AllowedValues\"], param[\"DataType\"], param[\"ParameterValue\"]]\nKeyError: 'AllowedValues'\n",
"module_stdout": "",
"msg": "MODULE FAILURE",
"rc": 0
}

# Fixed code
def main():
    argument_spec = ec2_argument_spec()
    argument_spec.update(
        dict(
            group_family=dict(
                type="str", choices=["memcached1.4", "redis2.6", "redis2.8", "redis3.2"]
            ),
            name=dict(required=True, type="str"),
            description=dict(default="", type="str"),
            state=dict(required=True),
            values=dict(type="dict"),
        )
    )
    module = AnsibleModule(argument_spec=argument_spec)

    if not HAS_BOTO3:
        module.fail_json(msg="boto required for this module")

    parameter_group_family = module.params.get("group_family")
    parameter_group_name = module.params.get("name")
    group_description = module.params.get("description")
    state = module.params.get("state")
    values = module.params.get("values")

    # Retrieve any AWS settings from the environment.
    region, ec2_url, aws_connect_kwargs = get_aws_connection_info(module, boto3=True)
    if not region:
        module.fail_json(
            msg="Either region or AWS_REGION or EC2_REGION environment variable or boto config aws_region or ec2_region must be set."
        )

    connection = boto3_conn(
        module,
        conn_type="client",
        resource="elasticache",
        region=region,
        endpoint=ec2_url,
        **aws_connect_kwargs,
    )

    exists = get_info(connection, parameter_group_name)

    # check that the needed requirements are available
    if state == "present" and not (exists or parameter_group_family):
        module.fail_json(msg="Creating a group requires a family group.")
    elif state == "reset" and not exists:
        module.fail_json(
            msg="No group %s to reset. Please create the group before using the state 'reset'."
            % parameter_group_name
        )

    # Taking action
    changed = False
    if state == "present":
        if exists:
            # confirm that the group exists without any actions
            if not values:
                response = exists
                changed = False
            # modify existing group
            else:
                modifiable_params = make_current_modifiable_param_dict(
                    module, connection, parameter_group_name
                )
                changed, values = check_valid_modification(
                    module, values, modifiable_params
                )
                response = modify(module, connection, parameter_group_name, values)
        # create group
        else:
            response, changed = create(
                module,
                connection,
                parameter_group_name,
                parameter_group_family,
                group_description,
            )
            if values:
                modifiable_params = make_current_modifiable_param_dict(
                    module, connection, parameter_group_name
                )
                changed, values = check_valid_modification(
                    module, values, modifiable_params
                )
                response = modify(module, connection, parameter_group_name, values)
    elif state == "absent":
        if exists:
            # delete group
            response, changed = delete(module, connection, parameter_group_name)
        else:
            response = {}
            changed = False
    elif state == "reset":
        response, changed = reset(module, connection, parameter_group_name, values)

    facts_result = dict(changed=changed, elasticache=camel_dict_to_snake_dict(response))

    module.exit_json(**facts_result)