| bag | A bag containg attributes and their values as strings. |
| cc | The context in which the values are retrieved. |
| converterFunc | A function to convert a string value to type T. |
| defaultValue | The value to return if the attribute is not found in the bag. |
T The attribute value from the bag, or defaultValue if the attribute is not found.
Get the attribute value from the attribute bag.
The attribute is looked up using name. If it is not found, each obsoleteNames is tried in turn, from first to last.