
from ..utils import requires_backends


a__				:      Optional[int]    		=     None






class     a_       :



       """simple docstring"""






       def __init__(		self				,       *_lowerCamelCase				,       **_lowerCamelCase   )					->str:
           requires_backends(self				,       ['''detectron2''']   )






       @classmethod
       def 	__lowerCAmelCase     (		cls				,       *_lowerCamelCase				,       **_lowerCamelCase   )					->Tuple:
           requires_backends(cls				,       ['''detectron2''']   )



"""simple docstring"""





def 							_lowerCAmelCase   (    UpperCAmelCase  :				int					):


					'''simple docstring'''






					if not isinstance(UpperCAmelCase   ,				UpperCAmelCase					):
										raise ValueError('''double_factorial() only accepts integral values'''					)
					if n < 0:
										raise ValueError('''double_factorial() not defined for negative values'''					)
					return 1 if n <= 1 else n * double_factorial(n - 2					)


if __name__ == "__main__":
				import doctest

				doctest.testmod()


