fuel/core — pull request #1118 by younes0 (2012-08-23 11:34:00+00:00)
Title: added Input::param_valid($key, $array)

Taken from Flourish:
http://flourishlib.com/docs/fRequest#RestrictingValidValues

The method param_valid() simplifies the process a great deal by taking
exactly two parameters, $key, the key to request the value for and
$valid_values, an array of permissible values. If the value is not one
of the valid value, the first valid value will be picked. Here is an
example: