How to have multiple synchronized shared types. Programming in D, page 647

[Brother Bill]

The idea is that multiple shared objects use a common lock.


```
import std.stdio;

void main()
{

}

class BankAccount
{

}

void transferMoney(shared BankAccount from,	shared BankAccount to)
{
	synchronized (from, to)    ← FAILS TO COMPILE.  Doesn't like 
comma.
	{ // ← correct
		// ...
	}
}

```

This fails to compile with dmd 2.111.0
```
c:\dev\D\81 - 90\c86_4f_multiple_synchronized\source\app.d(15): 
Error: using the result of a comma expression is not allowed
     synchronized (from, to)
                   ^
```

Is there another way to do this, other than manually, or is this 
obsolete?