# Build the OAuth post data.
	fun build_auth_body(code: String): HeaderMap do
		var map = new HeaderMap
		map["client_id"] = client_id
		map["client_secret"] = client_secret
		map["code"] = code
		var redirect_uri = self.redirect_uri
		if redirect_uri != null then map["redirect_uri"] = redirect_uri
		var state = self.state
		if state != null then map["state"] = state
		return map
	end