Argument.scan handles simple string to numeric type conversions, removing
the need to create a lambda. Argument.action is still necessary for more
complex conversions and those are left unchanged.
Signed-off-by: Sean Robinson <sean.robinson@scottsdalecc.edu>
The default behavior with optional arguments is to allow only a single use
per invocation. One alternative is to use .nargs, but this requires
previously knowing, and limiting, the quantity of values. The .append
method removes the restriction on repeats for a single Argument.
Signed-off-by: Sean Robinson <sean.robinson@scottsdalecc.edu>