sub sub_name{
  my ($self, %att) = @_; #
  
  $att{METHOD} or die "ERROR: Method not specified";

  my $url = $self->{URL};
  
  my $methodref = $self->{UA}->can ($att{METHOD}) 
                  or die "ERROR: No such METHOD: $att{METHOD}";
  $self->{RESPONSE} = $methodref->(  $self->{UA},
                                     $url ,
                                  ($att{VALUE}? ('Content' => to_json($att{VALUE})) 
                                           : ())
 );
 ...
}