sub size(){
    # setSize()
    # Returns the number of unique elements in bag.
    my $self = shift;
    my %dictionary = %{$self->{DICTIONARY}};
    # remove empty string key created by concat operation
    #delete  $self->{DICTIONARY}{''};
    
    return scalar keys (%dictionary);
    
}

##</code><code>##

sub size {
    # setSize()
    # Returns the number of unique elements in bag.
    return scalar keys %{ shift() };   
}