old_contents: """Simple Migrator."""
  __author__ = 'bkzhn'
  
  
  if __name__ == '__main__':
      print('== Simple Migrator ==')
  
new_contents: """Simple Migrator."""
  __author__ = 'bkzhn'
  
  connection_string = 'mysql+pymysql://root:1234@localhost/test'
  
  if __name__ == '__main__':
      print('== Simple Migrator ==')
  
subject: add connection_string