code: def value_at(self, x):
          
          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]
docs: 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