code: func (f *PluginFilter) pluginExistsOnNode(pluginType string, pluginName string, nodePlugins []api.PluginDescription) (bool, bool) {
  	var typeFound bool
  
  	for _, np := range nodePlugins {
  		if pluginType != np.Type {
  			continue
  		}
  		typeFound = true
  
  		if pluginName == np.Name {
  			return true, true
  		}
  		// This does not use the reference package to avoid the
  		// overhead of parsing references as part of the scheduling
  		// loop. This is okay only because plugin names are a very
  		// strict subset of the reference grammar that is always
  		// name:tag.
  		if strings.HasPrefix(np.Name, pluginName) && np.Name[len(pluginName):] == ":latest" {
  			return true, true
  		}
  	}
  	return typeFound, false
  }
docs: // pluginExistsOnNode returns true if the (pluginName, pluginType) pair is present in nodePlugins