Specifying __slots__ in a dynamically generated type

[Ron Garret]

I need to dynamically generate new types at run time.  I can do this in 
two ways.  I can use the "type" constructor, or I can generate a "class" 
statement as a string and feed that to the exec function.  The former 
technique is much cleaner all else being equal, but I want to be able to 
specify the __slots__ class variable for these new types, and it seems 
that to do that I need to use the latter method.  Is that true?  Is it 
really impossible to specify __slots__ using the "type" constructor?

rg