eFlag();
		}
	}

	/**
     * Calculate the minimum delay after the Nth automatic license
     * activation attempt.
     *
	 * @param int $attempt
	 * @return float|int Delay in seconds.
	 */
	private function calculateLicenseActivationDelay($attempt) {
		if ( $attempt < 1 ) {
			return 0;
		}

	    $minDelay = 20;
	    $maxDelay = 600;
	    $growthLimit = 4; //Stop increasing the delay after this many attempts.

        $fraction = (min($attempt - 1, $growthLimit) / ($growthLimit));

		$desiredDelay = $minDelay + round(($maxDelay - $minDelay) * $fraction);
		if ( $desiredDelay < $minDelay ) {
		    $desiredDelay = $minDelay;
        }
		return $desiredDelay;
	}

	public function clearActivationFailureFlag() {
	    delete_site_option(self::ACTIVATION_FAILURE_FLAG . $this->slug);
	}
}