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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 render(self):
 """ Returns the ``struct`` format and list of the size and value. The format is derived from the size primitive and the length of the resulting encoded value (e.g. the format for a string of 'foo' ends up as 'h3s'. .. note :: The value is expected to be string-able (wrapped in ``str()``) and is then encoded as UTF-8. """

        size_format = self.size_primitive.fmt

        if self.value is None:
            return size_format, [-1]

        value = self.render_value(self.value)

        size = len(value)

        fmt = "%s%ds" % (size_format, size)

        return fmt, [size, value]