public static final function fcm(string $string, string $separator = '_'): string {
		return ltrim(preg_replace_callback('/\\\?[A-Z][A-Za-z0-9]+?/', function($Macthes) use ($separator){
			return $separator . ltrim(strtolower($Macthes[0]), '\\');
		}, $string), $separator);
	}
public static final function fcm(string $string, string $separator = '_'): string {
		return ltrim(preg_replace_callback('/\\\?[A-Z][A-Za-z0-9]+?/', function($Macthes) use ($separator){
			return $separator . ltrim(strtolower($Macthes[0]), '\\');
		}, $string), $separator);
	}
public static final function fcm ( string $ string , string $ separator = '_' ) : string { return ltrim ( preg_replace_callback ( '/\\\?[A-Z][A-Za-z0-9]+?/' , function ( $ Macthes ) use ( $ separator ) { return $ separator . ltrim ( strtolower ( $ Macthes [ 0 ] ) , '\\' ) ; } , $ string ) , $ separator ) ; }
Convert any string from camel case to a string with a given delimiter.

@param string $string
@param string $separator
@return string
Convert any string from camel case to a string with a given delimiter .