operating system services keyword argument description callback_args optional positional arguments supplied to callback function specified with the callback argument optional keyword arguments supplied to callback function specified with the callback argument list of strings that specifies all possible option values used when an option only has limited set of values (for example['small''medium''large']the constant value that' stored with the 'store_constaction sets the default value of the option if not supplied by defaultthe default value is none sets the name of the attribute used to store option values during parsing normally the name is derived from the option name itself help text for this particular option if this is not suppliedthe option will be listed in help without description the value optparse suppress_help can be used to hide an option the special keyword '%defaultis replaced by the option default value in the help string specifies the name of an option argument that' used when printing help text specifies the number of option arguments for actions that expect arguments the default value is if number greater than is usedoption arguments will be collected into tuple that is then used whenever arguments are handled specifies the type of an option valid types are 'string(the default)'int''long''choice''float'and 'complexcallback_kwargs choices const default dest help metavar nargs type disable_interspersed_args(disallows the mixing of simple options with positional arguments for exampleif '-xand '-yare options that take no parametersthe options must appear before any arguments (for example'prog - - arg arg arg ' enable_interspersed_args(allows the mixing of options with positional arguments for exampleif '-xand '-yare simple options that take no parametersthey may be mixed with the argumentssuch as in 'prog - arg arg - arg this is the default behavior parse_args([arglist]parses command-line options and returns tuple (optionsargswhere options is an object containing the values of all the options and args is list of all the remaining positional arguments left over the options object stores all the option data in attributes with names that match the option name for examplethe option '--outputwould have its value stored in options output if the option does not appearthe value will be none the name of the attribute can be set using the dest keyword argument to add_option()described previously by defaultarguments are taken from sys argv[ :howevera different source of arguments can be supplied as an optional argumentarglist lib fl ff