get_child_by_name
Description:
Looks up a child element by the given name.
This virtual method has a default implementation that uses Object together with get_name. If the interface is to be used with Objects, this methods needs to be overridden.
Parameters:
| this | 
           the parent object to get the child from  | 
      
| name | 
           the child's name  | 
      
Returns:
| 
           the child object or null if not found.  |