code: 
  from __future__ import annotations
  
  
  
  class 			a      :
  
  
  
  
  
  
  		def __init__(  self	,     __UpperCamelCase							)->			int:
  						'''simple docstring'''
  
  
  						A__     :							List[str]   				=value
  						A__     :							Union[str, Any]   				=None
  						A__     :							List[Any]   				=None
  
  
  
  
  
  
  
  class 			a      :
  		__lowercase													=		42
  
  
  
  
  
  
  		def __init__(  self							)->			List[Any]:
  						'''simple docstring'''
  
  
  						A__     :							List[Any]   				=0
  
  
  
  
  
  
  		def       lowerCAmelCase_  (  self	,     __UpperCamelCase	,     __UpperCamelCase							)->			int:
  						'''simple docstring'''
  
  
  						if node is None:
  										return
  
  						if path_sum == self.target:
  										self.paths += 1
  
  						if node.left:
  										self.depth_first_search(node.left	,     path_sum + node.left.value							)
  						if node.right:
  										self.depth_first_search(node.right	,     path_sum + node.right.value							)
  
  
  
  
  
  
  		def       lowerCAmelCase_  (  self	,     __UpperCamelCase	,     __UpperCamelCase = None							)->			Union[str, Any]:
  						'''simple docstring'''
  
  
  						if node is None:
  										return 0
  						if target is not None:
  										A__     :							List[str]   				=target
  
  						self.depth_first_search(_lowerCAmelCase	,     node.value							)
  						self.path_sum(node.left							)
  						self.path_sum(node.right							)
  
  						return self.paths
  
  
  if __name__ == "__main__":
  						import doctest
  
  						doctest.testmod()
  
  
  
  
style_context: 
  
  
  def   SCREAMING_SNAKE_CASE__						(							snake_case_	)			->							int:
  				barcode //= 1_0  # exclude the last digit
  				A__     :							List[str]   				=False
  				A__     :							Dict   				=0
  
  				# extract and check each digit
  				while barcode != 0:
  								A__     :							Union[str, Any]   				=1 if checker else 3
  								s += mult * (barcode % 1_0)
  								barcode //= 1_0
  								A__     :							Union[str, Any]   				=not checker
  
  				return (1_0 - (s % 1_0)) % 1_0
  
  
  
  def   SCREAMING_SNAKE_CASE__						(							snake_case_	)			->							bool:
  				return len(str(snake_case_	)	) == 1_3 and get_check_digit(snake_case_	) == barcode % 1_0
  
  
  
  def   SCREAMING_SNAKE_CASE__						(							snake_case_	)			->							int:
  				if str(snake_case_	).isalpha():
  								A__     :							Tuple   				=f'Barcode \'{barcode}\' has alphabetic characters.'
  								raise ValueError(snake_case_	)
  				elif int(snake_case_	) < 0:
  								raise ValueError('''The entered barcode has a negative value. Try again.'''	)
  				else:
  								return int(snake_case_	)
  
  
  if __name__ == "__main__":
  						import doctest
  
  						doctest.testmod()
  						__lowerCamelCase       :       List[Any]				   =			get_barcode(input("Barcode: ").strip())
  
  						if is_valid(barcode):
  												print(F"'{barcode}' is a valid barcode.")
  						else:
  												print(F"'{barcode}' is NOT a valid barcode.")
  
  
  
  