'Replace I{child} with the specified I{content}.
@param child: A child element.
@type child: L{Element}
@param content: An element or collection of elements.
@type content: L{Element} or [L{Element},]'

def replaceChild(self, child, content):

    if (child not in self.children):
        raise Exception('child    not-found')
    index = self.children.index(child)
    self.remove(child)
    if (not isinstance(content, (list, tuple))):
        content = (content,)
    for node in content:
        self.children.insert(index, node.detach())
        node.parent = self
        index += 1
