lithium\storage\cache\Adapter::_addScopePrefix()
Adds scope prefix to keys using separator.
Parameters
- 
							string
							$scopeScope to use when prefixing. 
- 
							array
							$keysArray of keys either with or without mapping to values. 
- 
							string
							$separatorString to use when separating scope from key. 
Returns
arrayPrefixed keys array.
Source
	protected function _addScopePrefix($scope, array $keys, $separator = ':') {
		$results = [];
		$isMapped = !is_int(key($keys));
		foreach ($keys as $key => $value) {
			if ($isMapped) {
				$results["{$scope}{$separator}{$key}"] = $value;
			} else {
				$results[$key] = "{$scope}{$separator}{$value}";
			}
		}
		return $results;
	}