input: 
  from typing import List
  
  class VersionControl:
      def __init__(self, lines: List[str]):
          self.lines = lines
          self.mark = 0
   
      def commit(self):
          """ Record the current state of the lines and increment the mark. 
          Logs the state into a file named 'log_file.txt'.
          >>> version_control = VersionControl(["print('Hello')", "print('World')"])
          >>> version_control.commit()
          >>> version_control.mark
          1
          >>> with open("log_file.txt", "r") as f:
          ...     f.read()
          "1: ['print(\\'Hello\\')', 'print(\\'World\\')']"
          """
          self.mark += 1
          log_file = open("log_file.txt", "a+")
          log_file.write(str(self.mark) + ": " + str(self.lines) + "\n")
          log_file.close()
   
      def restore(self):
          """ Restore lines to the state recorded in the previous mark.
          >>> version_control = VersionControl(["print('Hello')", "print('World')"])
          >>> version_control.commit()
          >>> version_control.commit()
          >>> version_control.restore()
          >>> version_control.lines
          ['print(\'Hello\')', 'print(\'World\')']
          """
          log_file = open("log_file.txt", "r")
          lines = log_file.readlines()
          to_mark = self.mark-1
   
          self.lines = eval(lines[to_mark].split(": ", 1)[1])
          log_file.close()
  
output:     
          self.mark -= 1
  