BootswatchAsset.php
static function isSupportedTheme($theme)
	{
		if (! is_string($theme) || empty($theme)) {
			throw new InvalidCallException('Invalid theme value : empty or null value');
		}
		return file_exists(Yii::getAlias(BootswatchAsset::VENDOR_ALIAS . '/' . strtolower($theme) . '/bootstrap.min.css'));
	}
static function isSupportedTheme($theme)
	{
		if (! is_string($theme) || empty($theme)) {
			throw new InvalidCallException('Invalid theme value : empty or null value');
		}
		return file_exists(Yii::getAlias(BootswatchAsset::VENDOR_ALIAS . '/' . strtolower($theme) . '/bootstrap.min.css'));
	}
static function isSupportedTheme ( $ theme ) { if ( ! is_string ( $ theme ) || empty ( $ theme ) ) { throw new InvalidCallException ( 'Invalid theme value : empty or null value' ) ; } return file_exists ( Yii :: getAlias ( BootswatchAsset :: VENDOR_ALIAS . '/' . strtolower ( $ theme ) . '/bootstrap.min.css' ) ) ; }
Chekcs if a theme is a valid bootswatch theme.

This basic method assumes the $theme name passed as argument is an existing
subfolder of the vendor alias folder (@vendor/thomaspark/bootswatch) that contains
the file 'bootstrap.min.css'. If this condition is not true, the theme is invalid.

@param string $theme the theme name to test
@return boolean TRUE if $theme is a valid bootswatch theme, FALSE otherwise
Chekcs if a theme is a valid bootswatch theme .