old_contents: #
  # watermarking.py
  # Created by pira on 2017/07/26.
  #
  
  #coding: utf-8
  u"""Image Watermarking"""
  
  #using for add_lsb mode.
  TIME_DOMAIN = 1
  DCT_DOMAIN  = 0
  
  def add_lsb(cover, secret, mode=0):
  	u"""Embed 1 bit secret information by changing LSB.
   	@param  cover :cover data
   	@param  secret:secret data (1 bit)
   	@param  mode  :mode 0 is used for dct-domain, mode 1 is used for time-domain.(mode 1 avoids overflow that pxcel value is more than 255.)
   	@return stego :srego data
  	"""
  
  	if secret == 0:
  		if cover%2 == 0:
  			stego = cover
  		else:
  			stego = cover + 1
  			if mode == 1:
  				if stego > 255:
  					stego -= 2
  	elif secret == 1:
  		if cover%2 == 0:
  			stego = cover + 1
  		else:
  			stego = cover
  	return stego
  
  def check_lsb(data):
  	u"""Extract 1 bit secret information by chacking LSB.
   	@param  data   :stego data
   	@return secret :1 bit secret information
  	"""
  	if data%2 == 0:
  		return 0
  	elif data%2 == 1:
  		return 1
  
  def 
new_contents: #
  # watermarking.py
  # Created by pira on 2017/07/26.
  #
  
  #coding: utf-8
  u"""For image watermarking."""
  
  TIME_DOMAIN = 1
  DCT_DOMAIN  = 0
  
  def _add_lsb(cover, secret, mode=0):
  	u"""Embed 1 bit secret information by changing LSB.
   	@param  cover :cover data
   	@param  secret:secret data (1 bit)
   	@param  mode  :mode 0 is used for dct-domain, mode 1 is used for time-domain.(mode 1 avoids overflow that pxcel value is more than 255.)
   	@return stego :srego data
  	"""
  
  	if secret == 0:
  		if cover%2 == 0:
  			stego = cover
  		else:
  			stego = cover + 1
  			if mode == 1:
  				if stego > 255:
  					stego -= 2
  	elif secret == 1:
  		if cover%2 == 0:
  			stego = cover + 1
  		else:
  			stego = cover
  	return stego
  
  def _check_lsb(data):
  	u"""Extract 1 bit secret information by chacking LSB.
   	@param  data   :stego data
   	@return secret :1 bit secret information
  	"""
  
  	if data%2 == 0:
  		return 0
  	elif data%2 == 1:
  		return 1
  
  
subject: rewrite docstrings