code: def write_or_delete_file(self, what, filename, data, force=False):
          
          if data:
              self.write_file(what, filename, data)
          elif os.path.exists(filename):
              if data is None and not force:
                  log.warn(
                      "%s not set in setup(), but %s exists", what, filename
                  )
                  return
              else:
                  self.delete_file(filename)
docs: Write `data` to `filename` or delete if empty
  
          If `data` is non-empty, this routine is the same as ``write_file()``.
          If `data` is empty but not ``None``, this is the same as calling
          ``delete_file(filename)`.  If `data` is ``None``, then this is a no-op
          unless `filename` exists, in which case a warning is issued about the
          orphaned file (if `force` is false), or deleted (if `force` is true).