public function execute($query, array $variables = array())
	{
		// Build the request path.
		$path = '/graphql';

		$headers = array(
			'Accept'       => 'application/vnd.github.v4+json',
			'Content-Type' => 'application/json',
		);

		$data = array(
			'query' => $query,
		);

		if (!empty($variables))
		{
			$data['variables'] = $variables;
		}

		// Send the request.
		return $this->processResponse(
			$this->client->post($this->fetchUrl($path), json_encode($data), $headers)
		);
	}