Access the attribute metaclass from a typecoercion?

Stevan, Mooseniks,

I have a "DateTime" attribute trait that has a "date_format" like so:

has date_format => (
    is      => 'rw',
    isa     => 'Str',
    default => '%F %T',
);


I would like to have a type coercion that will use
DateTime::Format::Strptime to coerce a Str into a DateTime based on
that "date_format".

For that, I would need access to the attribute metaclass from the
"via" block.  Is there a way?

Dan