use v5.14;
use Data::Dumper;
use IO::File;

package MyClass {
	use Moo;
	has base_file => (
		is       => 'rw',
		required => 1,
		init_arg => 'base',
		coerce   => sub {
			my $base_fh = IO::File->new( $_[0], '<' ) or die "$_[0]: $!";
			$base_fh->binmode(":utf8");
			return $base_fh;
		},
	);
}

my $object = MyClass->new(base => __FILE__);
print Dumper($object->base_file);