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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def focus(self, f):
 """ Get a new UI proxy copy with the given focus. Return a new UI proxy object as the UI proxy is immutable. Args: f (2-:obj:`tuple`/2-:obj:`list`/:obj:`str`):
 the focus point, it can be specified as 2-list/2-tuple coordinates (x, y) in NormalizedCoordinate system or as 'center' or 'anchor'. Returns: :py:class:`UIObjectProxy <poco.proxy.UIObjectProxy>`: a new UI proxy object (copy) """


        ret = copy.copy(self)
        ret._focus = f
        return ret