old_contents: #!/usr/bin/env python
  
  # Copyright 2021 David Robillard <d@drobilla.net>
  # SPDX-License-Identifier: ISC
  
  import sys
  
  for filename in sys.argv[1:]:
      with open(filename, 'r') as f:
          sys.stdout.write(f.read())
  
new_contents: #!/usr/bin/env python3
  
  # Copyright 2021 David Robillard <d@drobilla.net>
  # SPDX-License-Identifier: ISC
  
  import sys
  
  for filename in sys.argv[1:]:
      with open(filename, 'r') as f:
          sys.stdout.write(f.read())
  
subject: Fix build on systems without a "python" executable