a ì)g˜ ã@s*ddlmZmZmZeZGdd„dƒZdS)é)Úabsolute_importÚdivisionÚprint_functionc@seZdZdZdd„ZdS)ÚSentinela0 Object which can be used to mark whether an entry as being special A sentinel value demarcates a value or marks an entry as having a special meaning. In C, the Null byte is used as a sentinel for the end of a string. In Python, None is often used as a Sentinel in optional parameters to mean that the parameter was not set by the user. You should use None as a Sentinel value any Python code where None is not a valid entry. If None is a valid entry, though, then you need to create a different value, which is the purpose of this class. Example of using Sentinel as a default parameter value:: def confirm_big_red_button(tristate=Sentinel): if tristate is Sentinel: print('You must explicitly press the big red button to blow up the base') elif tristate is True: print('Countdown to destruction activated') elif tristate is False: print('Countdown stopped') elif tristate is None: print('Waiting for more input') Example of using Sentinel to tell whether a dict which has a default value has been changed:: values = {'one': Sentinel, 'two': Sentinel} defaults = {'one': 1, 'two': 2} # [.. Other code which does things including setting a new value for 'one' ..] values['one'] = None # [..] print('You made changes to:') for key, value in values.items(): if value is Sentinel: continue print('%s: %s' % (key, value) cCs|S)a Return the cls itself. This makes both equality and identity True for comparing the class to an instance of the class, preventing common usage errors. Preferred usage:: a = Sentinel if a is Sentinel: print('Sentinel value') However, these are True as well, eliminating common usage errors:: if Sentinel is Sentinel(): print('Sentinel value') if Sentinel == Sentinel(): print('Sentinel value') ©)Úclsrrú:/usr/lib/python3.9/site-packages/ansible/utils/sentinel.pyÚ__new__1szSentinel.__new__N)Ú__name__Ú __module__Ú __qualname__Ú__doc__r rrrrr s'rN)Z __future__rrrÚtypeZ __metaclass__rrrrrÚs