code: def init_build(self, asset, builder):
          
          if not self.abs_path:
              rel_path = utils.prepare_path(self.rel_bundle_path)
              self.abs_bundle_path = utils.prepare_path([builder.config.input_dir, rel_path])
              self.abs_path = True
          self.input_dir = builder.config.input_dir
docs: Called when builder group collect files
          Resolves absolute url if relative passed
  
          :type asset: static_bundle.builders.Asset
          :type builder: static_bundle.builders.StandardBuilder