A boolean parameter that always gets filled in with a default value.

This Bool subclass forces autofill=True in Flag.__init__(). If no default is provided, it also fills in a default value of False. Lastly, unlike the Bool class, the default must be either True or False and cannot be None.

For example:

>>> flag = Flag('my_flag')
>>> (flag.autofill, flag.default)
(True, False)

To have a default value of True, create your Flag intance with default=True. For example:

>>> flag = Flag('my_flag', default=True)
>>> (flag.autofill, flag.default)
(True, True)

Also note that creating a Flag instance with autofill=False will have no effect. For example:

>>> flag = Flag('my_flag', autofill=False)
>>> flag.autofill