input: from typing import List
  
  
  class VersionControl:
      def __init__(self, lines: List[str]):
          self.lines = lines
          self.mark = 0
   
      def commit(self) -> None:
          """ Commits the current state of the lines to a log file and increments the mark.
          >>> vc = VersionControl(["print('Hello, World!')"])
          >>> vc.commit()
          >>> with open("log_file.txt", "r") as f:
          ...     print(f.read())
          1: ['print(\\'Hello, World!\\')']
          """
          self.mark += 1
          with open("log_file.txt", "a+") as log_file:
              log_file.write(str(self.mark) + ": " + str(self.lines))
   
      def restore(self) -> None:
          """ Restores the lines to the state of the previous commit mark.
          >>> vc = VersionControl(["print('Hello, World!')"])
          >>> vc.commit()
          >>> vc.lines = ["print('Goodbye!')"]
          >>> vc.commit()
          >>> vc.restore()
          >>> vc.lines
          ['print(\\)\\ \\'Hello, World!\\'\\)']
          """
          with open("log_file.txt", "r") as log_file:
              lines = log_file.readlines()
          to_mark = self.mark - 1
   
          self.lines = lines[to_mark]
output:     
          with open("log_file.txt", "r") as log_file:
              lines = log_file.readlines()
          to_mark = self.mark - 1
          if to_mark > 0:
              self.lines = eval(lines[to_mark - 1].split(": ")[1])
              self.mark = to_mark
  