#' This class represents the collection of storage accounts managed by a vault. It provides methods for adding and removing accounts, and doing backups and restores. For operations with a specific account, see [storage].
#' - `name`: A name by which to refer to the storage account.
#' - `storage_account`: The Azure resource ID of the account. This can also be an object of class `az_resource` or `az_storage`, as provided by the AzureRMR or AzureStor packages respectively; in this case, the resource ID is obtained from the object.
#' - `key_name`: The name of the storage access key that Key Vault will manage.
#' - `regen_key`: Whether to automatically regenerate the access key at periodic intervals.
#' - `regen_period`: How often to regenerate the access key. This can be a number, which will be interpreted as days; or as an ISO-8601 string denoting a duration, eg "P30D" (30 days).
#' - `attributes`: Optional attributes for the secret. A convenient way to provide this is via the [vault_object_attrs] helper function.
#' - `...`: For `create` and `import`, other named arguments which will be treated as tags.
#' - `confirm`: For `remove`, whether to ask for confirmation before removing the account.
#' - `backup`: For `restore`, a string representing the backup blob for a key.
#' - `email`: For `set_contacts`, the email addresses of the contacts.
#'
#' @section Value:
#' For `get` and `add`, an object of class `stored_account`, representing the storage account itself.
#'
#' For `list`, a vector of account names.
#'
#' For `backup`, a string representing the backup blob for a storage account. If the account has multiple versions, the blob will contain all versions.