Stores the values from the command line for the given known argument along with its various names (aliases).
The type of argument we should parse
Tries to convert the string value
to a true or false string value.
Tries to convert the string value
to a true or false string value. The value must be one of
T|True|F|False|Y|Yes|N|No ignoring case
Helper methods for looking up options, including their names, types, and values