input: def VersionControl(lines):
      """
      Implement a basic version control system in Python that keeps track of changes in the code.
      The function takes a list of code lines and supports two operations: commit and restore.
      On commit, it increments the version (mark) and writes the current state of the code to a log file.
      On restore, it reads the log file and restores the code to the previous state based on the current mark.
      
      Example:
      >>> VersionControl(['print("Hello, World!")', 'def greet():', '    return "Hello"']) == None
      True
      """
output:     import os
      import json
  
      def commit(lines, mark):
          with open('version_log.json', 'r') as f:
              log = json.load(f)
          log[mark] = lines
          with open('version_log.json', 'w') as f:
              json.dump(log, f)
          return mark + 1
  
      def restore(mark):
          with open('version_log.json', 'r') as f:
              log = json.load(f)
          return log[str(mark)]
  
      if not os.path.exists('version_log.json'):
          with open('version_log.json', 'w') as f:
              json.dump({}, f)
  
      mark = 0
      mark = commit(lines, mark)