# Get the n-th or innermost (if n = -1) argument of
# property. Empty string if property isn't parametrized
sub get_proparg {
  my $propstr = shift;         # get the property string
  my $level   = shift || 0;    # get the level we want to extract
  my $back    = $propstr;      # Initialize Return value (for case level=0)
  my $cnt;                     # initialize counter

  if($level == -1) {           # special case, get the innermost argument
    $propstr =~ /\(([^\(\)]+)\)+/;
    $propstr = $1;
  } else {                     # get whatever argument $level indicates
    for($cnt = 0;$cnt<$level; $cnt++) {
      $propstr =~ /\((.+)\)/;
      $propstr = $1;
    }
  }

  return $propstr;
}