python coding style question

[Werner LEMBERG]

In lilypond-book I see stuff like this:

  base = self.basename ()

  single = '%(base)s.png' % vars ()
  multiple = '%(base)s-page1.png' % vars ()

Why isn't this written as

  base = self.basename ()

  single = '%s.png' % base
  multiple = '%s-page1.png' % base

?  I could imagine that the latter gets executed faster, at least if
no .pyc files are created.

Is this just convenience or is this a question of coding style?


    Werner