code: 
  from __future__ import annotations
  
  import math
  import random
  
  
  
  def   SCREAMING_SNAKE_CASE__						(							snake_case_,	snake_case_,	snake_case_	)			->							list[int]:
  				A__     :							Optional[Any]   				=d * e - 1
  				A__     :							str   				=0
  				A__     :							Optional[int]   				=0
  				while p == 0:
  								A__     :							List[str]   				=random.randint(2,	n - 1	)
  								A__     :							Optional[int]   				=k
  								while True:
  												if t % 2 == 0:
  																A__     :							Dict   				=t // 2
  																A__     :							str   				=(g**t) % n
  																A__     :							Union[str, Any]   				=math.gcd(x - 1,	snake_case__	)
  																if x > 1 and y > 1:
  																				A__     :							int   				=y
  																				A__     :							List[str]   				=n // y
  																				break  # find the correct factors
  												else:
  																break  # t is not divisible by 2, break and choose another g
  				return sorted([p, q]	)
  
  
  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.")
  
  
  
  