code: func extractDocstring(body []syntax.Stmt) string {
  	if len(body) == 0 {
  		return ""
  	}
  	expr, ok := body[0].(*syntax.ExprStmt)
  	if !ok {
  		return ""
  	}
  	literal, ok := expr.X.(*syntax.Literal)
  	if !ok || literal.Token != syntax.STRING {
  		return ""
  	}
  	return literal.Value.(string)
  }
docs: // extractDocstring returns a doc string for the given body.
  //
  // A docstring is a string literal that comes first in the body, if any.