The Groovy system script to execute for determining the choices. The list returned from the script is treated as choices. It is treated as followings:
Here is an example:
Example1-----------------------------------------------------------------------------
// a simple example returning fixed choices.
return ["choice1", "choice2", "choice3"];
Example2-----------------------------------------------------------------------------
// choices 1,2,3,...,10.
return 1..10;
Example3-----------------------------------------------------------------------------
// today and last 6 days
return (6..0).collect{new Date().plus(-it).format("yyyy-MM-dd")};