'For internal use. Parse the XML content of the children of the
element.
Parameters
iterator : xml iterator
An iterator over XML elements as returned by
`~astropy.utils.xml.iterparser.get_xml_iterator`.
config : dict
The configuration dictionary that affects how certain
elements are read.
Returns
self : Element
Returns self as a convenience.'

def parse(self, iterator, config):

    raise NotImplementedError()
