def METHOD_NAME():
    """
        a
       / \
      b   c
     /   / \
    d   e   f
    """
    a = DOMNode(id="a")
    b = DOMNode(id="b")
    c = DOMNode(id="c")
    d = DOMNode(id="d")
    e = DOMNode(id="e")
    f = DOMNode(id="f")
    a._add_child(b)
    a._add_child(c)
    b._add_child(d)
    c._add_child(e)
    c._add_child(f)
    yield a