'Pull out the parent\'s namespaces, if there\'s no parent then default to
XML.'

def __init__(self, parent=None):

    self.parent = parent
    if (parent is not None):
        self.nss = OrderedDict(parent.nss)
    else:
        self.nss = {'http://www.w3.org/XML/1998/namespace': 'xml'}
