code: func (c *Config) DescendentForInstance(path addrs.ModuleInstance) *Config {
  	current := c
  	for _, step := range path {
  		current = current.Children[step.Name]
  		if current == nil {
  			return nil
  		}
  	}
  	return current
  }
docs: // DescendentForInstance is like Descendent except that it accepts a path
  // to a particular module instance in the dynamic module graph, returning
  // the node from the static module graph that corresponds to it.
  //
  // All instances created by a particular module call share the same
  // configuration, so the keys within the given path are disregarded.