sub create_list {
   my %dbs = map { $_ => 1 } qw/fetch forward user smtp/;
   delete @dbs{@_};
   return keys %dbs;
}

##</code><code>##

use Quantum::Superpositions;

sub create_list {
   my $dbs  = any qw/fetch forward user smtp/;
   my $skip = all @_;
   return eigenstates( $dbs ne $skip );
}

##</code><code>##

use Set::Scalar qw( );

sub create_list {
   my $dbs  = Set::Scalar->new( qw/fetch forward user smtp/ );
   my $skip = Set::Scalar->new( @_ );
   return ($dbs - $skip)->members();
}