code: def export_private_key(self, password=None):
  		
  
  		if self.__private_key is None:
  			raise ValueError('Unable to call this method. Private key must be set')
  
  		if password is not None:
  			if isinstance(password, str) is True:
  				password = password.encode()
  			return self.__private_key.private_bytes(
  				encoding=serialization.Encoding.PEM,
  				format=serialization.PrivateFormat.PKCS8,
  				encryption_algorithm=serialization.BestAvailableEncryption(password)
  			)
  		return self.__private_key.private_bytes(
  			encoding=serialization.Encoding.PEM,
  			format=serialization.PrivateFormat.TraditionalOpenSSL,
  			encryption_algorithm=serialization.NoEncryption()
  		)
docs: Export a private key in PEM-format
  
  		:param password: If it is not None, then result will be encrypt with given password
  		:return: bytes