public function getRepositoryList($owner, $repo, $sort = 'created', $direction = 'asc', Date $since = null)
	{
		// Build the request path.
		$path = '/repos/' . $owner . '/' . $repo . '/issues/comments';

		if (false == in_array($sort, array('created', 'updated')))
		{
			throw new \UnexpectedValueException(
				sprintf(
					'%1$s - sort field must be "created" or "updated"', __METHOD__
				)
			);
		}

		if (false == in_array($direction, array('asc', 'desc')))
		{
			throw new \UnexpectedValueException(
				sprintf(
					'%1$s - direction field must be "asc" or "desc"', __METHOD__
				)
			);
		}

		$path .= '?sort=' . $sort;
		$path .= '&direction=' . $direction;

		if ($since)
		{
			$path .= '&since=' . $since->toISO8601();
		}

		// Send the request.
		return $this->processResponse($this->client->get($this->fetchUrl($path)));
	}