input: 
  def VersionControl(lines: str) -> None:
      """Implement a version control system that keeps track of changes in the code. 
      The system should have methods to commit changes and restore to a previous state. 
      The changes should be logged in a file named "log_file.txt".
      Example:
      VersionControl("print('Hello, World!')")
      """
  
output:     
      with open("log_file.txt", "a") as log_file:
          log_file.write(f"Commit: {lines}\n")
  