'Process (marshal) the tag with the specified value using the
optional type information.
@param value: The value (content) of the XML node.
@type value: (L{Object}|any)
@param tag: The (optional) tag name for the value.  The default is
value.__class__.__name__
@type tag: str
@return: An xml node.
@rtype: L{Element}'

def process(self, value, tag=None):

    content = Content(tag=tag, value=value)
    result = Core.process(self, content)
    return result
