'Return the value of a stanza interface.
If the found value is None or an empty string, return the supplied
default value.
Allows stanza objects to be used like dictionaries.
:param string key: The name of the stanza interface to check.
:param default: Value to return if the stanza interface has a value
of ``None`` or ``""``. Will default to returning None.'

def get(self, key, default=None):

    value = self[key]
    if ((value is None) or (value == u'')):
        return default
    return value
