code: 
  """simple docstring"""
  import os
  import sys
  import time
  
  from . import transposition_cipher as trans_cipher
  
  
  
  
  def     __lowerCamelCase  (		):
  
  
  	"""simple docstring"""
  
  
  
  
  
  
  	_UpperCAmelCase =						'''Prehistoric Men.txt'''
  	_UpperCAmelCase =						'''Output.txt'''
  	_UpperCAmelCase =						int(input("Enter key: "      )      )
  	_UpperCAmelCase =						input("Encrypt/Decrypt [e/d]: "      )
  
  	if not os.path.exists(snake_case_      ):
  		print(f"File {input_file} does not exist. Quitting..."      )
  		sys.exit()
  	if os.path.exists(snake_case_      ):
  		print(f"Overwrite {output_file}? [y/n]"      )
  		_UpperCAmelCase =						input("> "      )
  		if not response.lower().startswith("y"      ):
  			sys.exit()
  
  	_UpperCAmelCase =						time.time()
  	if mode.lower().startswith("e"      ):
  		with open(snake_case_      ) as f:
  			_UpperCAmelCase =						f.read()
  		_UpperCAmelCase =						trans_cipher.encrypt_message(snake_case_				,     snake_case_      )
  	elif mode.lower().startswith("d"      ):
  		with open(snake_case_      ) as f:
  			_UpperCAmelCase =						f.read()
  		_UpperCAmelCase =						trans_cipher.decrypt_message(snake_case_				,     snake_case_      )
  
  	with open(snake_case_				,     "w"      ) as output_obj:
  		output_obj.write(snake_case_      )
  
  	_UpperCAmelCase =						round(time.time() - start_time				,     2      )
  	print(("Done (", total_time, "seconds )")      )
  
  
  if __name__ == "__main__":
  			main()
  
  
  
  
  
style_context: 
  """simple docstring"""
  from .stack import Stack
  
  
  
  
  def     __lowerCamelCase  (		UpperCamelCase__      ):
  
  
  	"""simple docstring"""
  
  
  
  
  
  
  	_UpperCAmelCase =						Stack()
  	_UpperCAmelCase =						{"(": ")", "[": "]", "{": "}"}
  	for bracket in parentheses:
  		if bracket in bracket_pairs:
  			stack.push(UpperCamelCase__      )
  		elif bracket in (")", "]", "}"):
  			if stack.is_empty() or bracket_pairs[stack.pop()] != bracket:
  				return False
  	return stack.is_empty()
  
  
  if __name__ == "__main__":
  			from doctest import testmod
  
  			testmod()
  
  			__magic_name__		       =				['''((()))''', '''((())''', '''(()))''']
  			print('''Balanced parentheses demonstration:\n''')
  			for example in examples:
  						__magic_name__		       =				'''''' if balanced_parentheses(example) else '''not '''
  						print(f'''{example} is {not_str}balanced''')
  
  
  
  
  