'Return a copy of the :class:`Bbox`, shifted to position *c*
within a container.
*c*: may be either:
* a sequence (*cx*, *cy*) where *cx* and *cy* range from 0
to 1, where 0 is left or bottom and 1 is right or top
* a string:
- \'C\' for centered
- \'S\' for bottom-center
- \'SE\' for bottom-left
- \'E\' for left
- etc.
Optional argument *container* is the box within which the
:class:`Bbox` is positioned; it defaults to the initial
:class:`Bbox`.'

def anchored(self, c, container=None):

    if (container is None):
        container = self
    (l, b, w, h) = container.bounds
    if isinstance(c, six.string_types):
        (cx, cy) = self.coefs[c]
    else:
        (cx, cy) = c
    (L, B, W, H) = self.bounds
    return Bbox((self._points + [((l + (cx * (w - W))) - L), ((b + (cy * (h - H))) - B)]))
