Created the arg_check.is_val_or_list() function for the value.set user function.
The value argument of this user function is now classified as a 'val_or_list' object, hence this is_val_or_list() replaces the use of is_str_or_num_or_str_num_list().
Authored by: bugman 2012-05-13
Parent: [r16258]
Child: [r16260]