6.21.3.10 Other methods

OptionParser supports several other public methods:

set_usage(usage)
Set the usage string according to the rules described above for the usage constructor keyword argument. Passing None sets the default usage string; use SUPPRESS_USAGE to suppress a usage message.
enable_interspersed_args(), disable_interspersed_args()
Enable/disable positional arguments interspersed with options, similar to GNU getopt (enabled by default). For example, if "-a" and "-b" are both simple options that take no arguments, optparse normally accepts this syntax:
```
prog -a arg1 -b arg2
```
and treats it as equivalent to
```
prog -a -b arg1 arg2
```
To disable this feature, call disable_interspersed_args(). This restores traditional Unix syntax, where option parsing stops with the first non-option argument.

set_defaults(dest=value, ...)

Set default values for several option destinations at once. Using set_defaults() is the preferred way to set default values for options, since multiple options can share the same destination. For example, if several ``mode'' options all set the same destination, any one of them can set the default, and the last one wins:

parser.add_option("--advanced", action="store_const",
                  dest="mode", const="advanced",
                  default="novice")    # overridden below
parser.add_option("--novice", action="store_const",
                  dest="mode", const="novice",
                  default="advanced")  # overrides above setting

To avoid this confusion, use set_defaults():

parser.set_defaults(mode="advanced")
parser.add_option("--advanced", action="store_const",
                  dest="mode", const="advanced")
parser.add_option("--novice", action="store_const",
                  dest="mode", const="novice")

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