old_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  
  from puchikarui.puchikarui import Schema, Execution, DataSource, Table
  
  __all__ = ["Schema", "Execution", "DataSource", "Table"]
  
new_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  
  from .puchikarui import Schema, Execution, DataSource, Table
  
  __all__ = ["Schema", "Execution", "DataSource", "Table"]
  
subject: Use relative import