code: def get_migration(plugin, filename):
      '''Get an existing migration record if exists'''
      db = get_db()
      return db.migrations.find_one({'plugin': plugin, 'filename': filename}f get_migration(plugin, filename):
      '''Get an existing migration record if exists'''
      db = get_db()
      return db.migrations.find_one({'plugin': plugin, 'filename': filename})
docs: Get an existing migration record if exists