input: from typing import List
  
  class VersionControl:
      def __init__(self, lines: List[str]):
          self.lines = lines
          self.mark = 0
   
      def commit(self) -> None:
          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:
          with open("log_file.txt", "r") as log_file:
              lines = log_file.readlines()
              to_mark = self.mark-1
   
          self.lines = eval(lines[to_mark].split(": ")[1])
  
  # Example usage:
  # vc = VersionControl(["print('Hello, World!')"])
  # vc.commit()
  # vc.restore()
output:     def rollback(self) -> None:
          with open("log_file.txt", "r") as log_file:
              lines = log_file.readlines()
              if self.mark > 1:
                  self.mark -= 1
                  to_mark = self.mark-1
                  self.lines = eval(lines[to_mark].split(": ")[1])
  
      def forward(self) -> None:
          with open("log_file.txt", "r") as log_file:
              lines = log_file.readlines()
              if self.mark < len(lines):
                  self.mark += 1
                  to_mark = self.mark-1
                  self.lines = eval(lines[to_mark].split(": ")[1])