...
A
...
class
...
that
...
is
...
supposed
...
to
...
be
...
used
...
only
...
as
...
a
...
mixin
...
has
...
the
...
suffix
...
"Mixin"
...
at
...
...
.
...
Not
...
all
...
classes
...
can
...
only
...
be
...
used
...
as
...
a
...
mixin,
...
however.
...
Such
...
classes
...
don't
...
have
...
the
...
suffix
...
"Mixin".
...
An
...
example
...
for
...
this
...
is
...
the
...
elaboration
...
on
...
DessertTopping
...
vs.
...
DessertToppingMixin
...
.
...
It
...
can
...
be
...
found
...
here:
...
...
...
...
...
...
...
...
...
...
...
...
.
...
Whether
...
you
...
stick
...
to
...
this
...
convention
...
or
...
not
...
is
...
a
...
matter
...
of
...
taste
...
(unless
...
you
...
work
...
for
...
rubicon,
...
where
...
the
...
"mixin"
...
convention
...
is
...
mandatory).
...
All
...
examples
...
in
...
this
...
tutorial
...
use
...
this
...
convention,
...
however.