input: 
  class VersionControl:
      """A basic version control system that keeps track of changes in the code.
      The system supports committing changes and restoring to a previous version.
      
      For example:
      vc = VersionControl([1, 2, 3])
      vc.commit()
      vc.lines = [1, 2, 4]
      vc.commit()
      vc.restore()
      print(vc.lines)  # Output: [1, 2, 3]
      """
      def __init__(self, lines):
          self.lines = lines
          self.mark = 0
   
      def commit(self):
          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):
          log_file = open("log_file.txt", "r")
          lines = log_file.readlines()
          to_mark = self.mark-1
   
          self.lines = [int(x) for x in lines[to_mark].split(": ")[1][:-2].split(", ")]
          log_file.close()
  
output:     
          self.mark -= 1
  