code: def setIV(self, IV):
  		
  		if not IV or len(IV) != self.block_size:
  			raise ValueError("Invalid Initial Value (IV), must be a multiple of " + str(self.block_size) + " bytes")
  		IV = self._guardAgainstUnicode(IV)
  		self._iv = IV
docs: Will set the Initial Value, used in conjunction with CBC mode