input: Write a function that implements a basic version control system in Python. The function should include an `__init__` method to initialize the version control system with a list of lines, a `commit` method to save the current state of the list to a log file, and a `restore` method to revert the list to the previous saved state. The function should be able to handle the creation and reading of a log file for tracking changes.
  class VersionControl:
      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
          if to_mark >= 0:
              self.lines = eval(lines[to_mark].split(": ", 1)[1])
          else:
              self.lines = []
          log_file.close()
  
  assert VersionControl(["line1", "line2"]).commit() is None
  assert VersionControl(["line1", "line2"]).restore() == ["line1", "line2"]
  assert VersionControl([]).commit() is None
  assert VersionControl([]).restore() == []
output: 
  class VersionControl:
      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
          if to_mark >= 0:
              self.lines = eval(lines[to_mark].split(": ", 1)[1])
          else:
              self.lines = []
          log_file.close()
  