The Broken Hourglass Weekly Update

Planewalker Games' official website has received its usual weekly update for The Broken Hourglass, this time presenting us with the code used to generate tailored groups of creatures in the game.
Here's a partial explanation of the optional arguments.

?hostile? : (default true) Determines whether the generated creatures should be hostile or neutral.

?size?: (default 1-1) The desired range of creatures this function should output, expressed like a point coordinate: asking for 1-3 creatures is expressed as ?size= 1::3?

?challenge?: (defaults to challenge rating of the player party) How powerful the encounter should be. Note that this allows us to make encounters both of fixed (predefined) challenge rating, as well as with a dynamic (scaled) challenge rating.

?join_party?: If set to a party, the newly generated creatures will join that party. Useful for situations where a fixed, predefined CREATURE needs flexibly defined minions/support staff.

?hiding?: (default false) If true, the newly generated creatures will (try to) be hiding.