<p>With a class in Python, how do I define a function to print every single instance of the class in a format defined in the function?</p>

Same as almost all other OO languages, keep all instances of the class in a collection of some kind.
You can try this kind of thing.
```
```
class MyClassFactory( object ):
    theWholeList= []
    def __call__( self, *args, **kw ):
         x= MyClass( *args, **kw )
         self.theWholeList.append( x )
         return x
```
```
Now you can do this.
```
```
object= MyClassFactory( args, ... )
print MyClassFactory.theWholeList
```
```