my $self=ParantClass->new();

##</code><code>##

# in the parent class:
sub new {
  my ($class) = @_;
  my $self = bless { },$class;
  # ...
  return $self;
}

# in the child class:
# if you really need to override the constructor
# you can use this:

sub new {
  my ($class) = @_;
  my $self = $class->SUPER::new();  # call parent constructor
  # ....
  return $self;
}