code: func (c *Config) Depth() int {
  	ret := 0
  	this := c
  	for this.Parent != nil {
  		ret++
  		this = this.Parent
  	}
  	return ret
  }
docs: // Depth returns the number of "hops" the receiver is from the root of its
  // module tree, with the root module having a depth of zero.