Associates two functions with group which will be called
from OptionContext.parse before the first option is parsed
and after the last option has been parsed, respectively.
Note that the user data to be passed to pre_parse_func and
post_parse_func can be specified when constructing the group
with OptionGroup.new.
Associates two functions with group which will be called from OptionContext.parse before the first option is parsed and after the last option has been parsed, respectively.
Note that the user data to be passed to pre_parse_func and post_parse_func can be specified when constructing the group with OptionGroup.new.