code: def _plugin_targets(self, compiler):
      
      if compiler == 'javac':
        plugin_cls = JavacPlugin
      elif compiler == 'scalac':
        plugin_cls = ScalacPlugin
      else:
        raise TaskError('Unknown JVM compiler: {}'.format(compiler))
      plugin_tgts = self.context.targets(predicate=lambda t: isinstance(t, plugin_cls))
      return {t.plugin: t.closure() for t in plugin_tgts}
docs: Returns a map from plugin name to the targets that build that plugin.