code: public static function isKeyCaseSensitive($caseSensitive, $key)
      {
          if (\is_array($caseSensitive)) {
              return isset($caseSensitive[$key]) ? $caseSensitive[$key] : true;
          }
  
          return $caseSensitive;
      }
docs: A helper method used to find out whether or not a certain input token has to be case-sensitively matched.
  
  @param array<int, bool>|bool $caseSensitive global case sensitiveness or an array of booleans, whose keys should match
  the ones used in $others. If any is missing, the default case-sensitive
  comparison is used
  @param int                   $key           the key of the token that has to be looked up
  
  @return bool