A class to hold information about a parameter for a commandline.

Do not use this directly, instead use one of the subclasses.

Attributes:

• names -- a list of string names by which the parameter can be referenced (ie. ["-a", "--append", "append"]). The first name in the list is considered to be the one that goes on the commandline, for those parameters that print the option. The last name in the list is assumed to be a "human readable" name describing the option in one word.

• param_type -- a list of string describing the type of parameter, which can help let programs know how to use it. Example descriptions include input, output, file

• checker_function -- a reference to a function that will determine if a given value is valid for this parameter.

• description -- a description of the option.

• is_required -- a flag to indicate if the parameter must be set for the program to be run.

• is_set -- if the parameter has been set

• value -- the value of a parameter

__init__ (
        self,
        names=[],
        types=[],
        checker_function=None,
        is_required=0,
        description="",
        )