code: 
  
  
  import os
  import sys
  import time
  
  from . import transposition_cipher as trans_cipher
  
  
  def 							SCREAMING_SNAKE_CASE					(  )    ->  None:
  						_a     =			'Prehistoric Men.txt'
  						_a     =			'Output.txt'
  						_a     =			int(input('Enter key: '				)				)
  						_a     =			input('Encrypt/Decrypt [e/d]: '				)
  
  						if not os.path.exists(_UpperCAmelCase				):
  												print(f"""File {input_file} does not exist. Quitting..."""				)
  												sys.exit()
  						if os.path.exists(_UpperCAmelCase				):
  												print(f"""Overwrite {output_file}? [y/n]"""				)
  												_a     =			input('> '				)
  												if not response.lower().startswith('y'				):
  																		sys.exit()
  
  						_a     =			time.time()
  						if mode.lower().startswith('e'				):
  												with open(_UpperCAmelCase				) as f:
  																		_a     =			f.read()
  												_a     =			trans_cipher.encrypt_message(_UpperCAmelCase							,     _UpperCAmelCase				)
  						elif mode.lower().startswith('d'				):
  												with open(_UpperCAmelCase				) as f:
  																		_a     =			f.read()
  												_a     =			trans_cipher.decrypt_message(_UpperCAmelCase							,     _UpperCAmelCase				)
  
  						with open(_UpperCAmelCase							,     'w'				) as output_obj:
  												output_obj.write(_UpperCAmelCase				)
  
  						_a     =			round(time.time() - start_time							,     2				)
  						print(('Done (', total_time, 'seconds )')				)
  
  
  if __name__ == "__main__":
  		main()
  
  
  
style_context: 
  
  
  import math
  
  
  def 							SCREAMING_SNAKE_CASE					(  _UpperCAmelCase				)    ->  float:
  						_a     =			math.log(2							,     10				) * number
  						_a     =			round((log_number - int(_UpperCAmelCase				))							,     15				)
  
  						return difference
  
  
  def 							SCREAMING_SNAKE_CASE					(  _UpperCAmelCase = 678910				)    ->  int:
  						_a     =			90
  						_a     =			0
  
  						_a     =			math.log(1.23							,     10				)
  						_a     =			math.log(1.24							,     10				)
  						_a     =			0
  
  						while position < number:
  												_a     =			log_difference(_UpperCAmelCase				)
  
  												if difference >= upper_limit:
  																		power_iterator += 93
  
  												elif difference < lower_limit:
  																		power_iterator += 196
  
  												else:
  																		_a     =			power_iterator
  																		power_iterator += 196
  																		position += 1
  
  						return previous_power
  
  
  if __name__ == "__main__":
  		import doctest
  
  		doctest.testmod()
  
  		print(f"""{solution() = }""")
  
  
  