Retrieve reverse label

There is currently a function that retrieves he relation label

function relation_get_type_label($relation) {
  $type = relation_type_load($relation->relation_type);
  return $type->label;
}

We can modify if easily and retrieve the reverse label as well

function relation_get_type_label($relation, $reverse = FALSE) {
  $type = relation_type_load($relation->relation_type);
  
  if ($type->directional == 0) {
     return $type->label; 
  } 
  else {
    return (!$reverse) ? $type->label : $type->reverse_label; 
  }
}