ditions.
     *
     * Example: Application component unavailable, unexpected exception.
     *
     * @param string  $message
     * @param mixed[] $context
     *
     * @return void
     */
    public function critical($message, array $context = array());

    /**
     * Runtime errors that do not require immediate action but should typically
     * be logged and monitored.
     *
     * @param string  $message
     * @param mixed[] $context
     *
     * @return void
     */
    public function error($message, array $context = array());

    /**
     * Exceptional occurrences that are not errors.
     *
     * Example: Use of deprecated APIs, poor use of an API, undesirable things
     * that are not necessarily wrong.
     *
     * @param string  $message
     * @param mixed[] $context
     *
     * @return void
     */
    public function warning($message, array $context = array());

    /**
     * Normal but significant events.
     *
     * @param string  $message
     * @param mixed[] $context
     *
     * @return void
     */
    public function notice($message, array $context = array());

    /**
     * Interesting events.
     *
     * Example: User logs in, SQL logs.
     *
     * @param string  $message
     * @param mixed[] $context
     *
     * @return void
     */
    public function info($message, array $context = array());

    /**
     * Detailed debug information.
     *
     * @param string  $message
     * @param mixed[] $context
     *
     * @return void
     */
    public function debug($message, array $context = array());

    /**
     * Logs with an arbitrary level.
     *
     * @param mixed   $level
     * @param string  $message
     * @param mixed[] $context
     *
     * @return void
     *
     * @throws \Psr\Log\InvalidArgumentException
     */
    public function log($level, $message, array $context = array());
}
<br />
<b>Fatal error</b>:  Uncaught Error: Interface &quot;Psr\Log\LoggerInterface&quot; not found in /home/cmonclan/www/cmonclan/core/lib/Drupal/Core/Logger/LoggerChannelInterface.php:35
Stack trace:
#0 /home/cmonclan/www/cmonclan/vendor/composer/ClassLoader.php(571): include()
#1 /home/cmonclan/www/cmonclan/vendor/composer/ClassLoader.php(428): Composer\Autoload\includeFile('/home/cmonclan/...')
#2 /home/cmonclan/www/cmonclan/core/lib/Drupal/Core/Logger/LoggerChannel.php(14): Composer\Autoload\ClassLoader-&gt;loadClass('Drupal\\Core\\Log...')
#3 /home/cmonclan/www/cmonclan/vendor/composer/ClassLoader.php(571): include('/home/cmonclan/...')
#4 /home/cmonclan/www/cmonclan/vendor/composer/ClassLoader.php(428): Composer\Autoload\includeFile('/home/cmonclan/...')
#5 /home/cmonclan/www/cmonclan/core/lib/Drupal/Core/Logger/LoggerChannelFactory.php(34): Composer\Autoload\ClassLoader-&gt;loadClass('Drupal\\Core\\Log...')
#6 /home/cmonclan/www/cmonclan/core/includes/install.core.inc(371): Drupal\Core\Logger\LoggerChannelFactory-&gt;get('file')
#7 /home/cmonclan/www/cmonclan/core/includes/install.core.inc(116): install_begin_request(Object(Composer\Autoload\ClassLoader), Array)
#8 /home/cmonclan/www/cmonclan/core/install.php(48): install_drupal(Object(Composer\Autoload\ClassLoader))
#9 {main}
  thrown in <b>/home/cmonclan/www/cmonclan/core/lib/Drupal/Core/Logger/LoggerChannelInterface.php</b> on line <b>35</b><br />