     /**
     Helper function for evaluating the path to a database for easy use in the YapDatabase constructor.
     
-    :param: directory a NSSearchPathDirectory value, use .DocumentDirectory for production.
-    :param: name a String, the name of the sqlite file.
-    :param: suffix a String, will be appended to the name of the file.
-    
-    :returns: a String
+    - parameter directory: a NSSearchPathDirectory value, use .DocumentDirectory for production.
+    - parameter name: a String, the name of the sqlite file.
+    - parameter suffix: a String, will be appended to the name of the file.
+    
+    - returns: a String
     */
     public static func pathToDatabase(directory: NSSearchPathDirectory, name: String, suffix: String? = .None) -> String {
         let paths = NSSearchPathForDirectoriesInDomains(directory, .UserDomainMask, true)

Note that it is preferable to use this exclusively to ensure
a consistent key structure.

:param: persistable A Persistable type instance
:returns: A String
*/
public func keyForPersistable<P: Persistable>(persistable: P) -> String {
    return "\(persistable.identifier)"

A simple function which generates a YapDB.Index from a Persistable
instance. All write(_:) store objects in the database using this function.

- parameter persistable: A Persistable type instance
- returns: A YapDB.Index
*/
public func indexForPersistable<P: Persistable>(persistable: P) -> YapDB.Index {
    return YapDB.Index(collection: persistable.dynamicType.collection, key: keyForPersistable(persistable))
