Thread.sleep( dur!("msecs")( 50 ) ); // sleep for 50 milliseconds

[Suliman via Digitalmars-d-learn]

     	foreach(f; files))
     	{
     		if (canFind(to!string(f), " "))
     		{
     			writeln("whitespace found:");
     			writeln(f);
     			Thread.sleep( dur!("msecs")( 50 ) );  // sleep for 50 
milliseconds
     		}
     		else
     			continue;
     	}

Error: module app struct std.regex.Thread(DataIndex) is private
Error: no property 'sleep' for type 'void'

What's wrong? Why sleeping do not work?