class_type 'DateTime';

subtype 'My::Model::Support::Ticket::Str' => as 'Str';
subtype 'My::Model::Support::Ticket::Int' => as 'Int';

coerce 'DateTime',
  from 'My::Model::Support::Ticket::Str',
  via { DateTime::Format::DateParse->parse_datetime($_) };

coerce 'DateTime',
  from 'My::Model::Support::Ticket::Int',
  via { DateTime->from_epoch( epoch => $_ ) };

...

has created_time => (
    is       => 'rw',
    isa      => 'DateTime',
    required => 0,
    coerce   => 1,
);