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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 value_at(self, x):
 """Return the value of this `Series` at the given `xindex` value Parameters x : `float`, `~astropy.units.Quantity` the `xindex` value at which to search Returns ------- y : `~astropy.units.Quantity` the value of this Series at the given `xindex` value """

        x = Quantity(x, self.xindex.unit).value
        try:
            idx = (self.xindex.value == x).nonzero()[0][0]
        except IndexError as e:
            e.args = ("Value %r not found in array index" % x,)
            raise
        return self[idx]