linked_policies

Create a policy with the term of the dialog's policy's current revision and link it to that policy.

Code
Needs ``britecore/policies/newPolicy`` rw too. Stacked ``requires_permission`` decorators do not require both
(only the outer one is read, and the gateway accepts any one of a list), so that permission is checked here.

Parameters
----------
params : dict
    ``policy_id`` (str, required).

Returns
-------
dict
    ``policy_id``: the new policy.

Return the policy's group and the policies the dialog lists. Writes nothing.

Code
Parameters
----------
params : dict
    ``policy_id`` (str, required): the policy whose page shows the dialog.

Returns
-------
dict
    ``group_id`` (null when the policy is in no group), ``group_billing_number`` (with no group: the number that
    a new group of the policy gets) and ``policies``: the policy first, then the active and application policies
    of the group by date added, each with ``policy_id``, ``policy_number``, ``policy_type_name``, ``is_gen3``,
    ``named_insured``, ``mailing_address`` and ``exclude_from_billing``.

Link a policy to the group of the dialog's policy; create the group when the policy has none.

Code
A policy cannot be linked to itself. When the target is in another group and ``move_if_linked`` is false, nothing
changes and ``requires_move_confirmation`` is true: ask the user, then send the request again with
``move_if_linked`` true. The move deletes the old group when one policy stays in it, and renumbers it when it was
named after the target.

Parameters
----------
params : dict
    ``policy_id`` (str, required), ``target_policy_id`` (str, required), ``move_if_linked`` (bool, default
    false).

Returns
-------
dict
    ``linked``, ``requires_move_confirmation``, ``message`` (show it when ``linked`` is false or the group was
    renumbered), and when linked: ``group_id``, ``group_billing_number`` and ``account_number`` (the linked
    policy's).

Remove a policy (it can be the dialog's policy itself) from the group of the dialog's policy.

Code
A group of two is dissolved. A larger group whose number ends with the removed policy's number gets the number
of another of its policies, and ``message`` says so. Refused with a message when the dialog's policy is in no
group of two or more, or when the target is not in its group (the group changed after the dialog read it).

Parameters
----------
params : dict
    ``policy_id`` (str, required), ``target_policy_id`` (str, required).

Returns
-------
dict
    ``message`` (empty, or the renumbering notice), ``group_id`` (null when the group was dissolved),
    ``group_billing_number`` (the group's number; after a dissolve, the number a new group of the policy gets)
    and ``account_number`` (the dialog's policy's).