def METHOD_NAME(self):
    channel_to_child = []  # For each index in .power, the corresponding child
    for spec in self.dev.spectra.value:
        for c in (self.dependency1, self.dependency2):
            if any(spec == cs for cs in c.spectra.value):
                channel_to_child.append(c)
                break
        else:
            raise ValueError("Failed to find spectra %s in children" % (spec,))
    # The first and last ones are normally always from different children
    c1 = channel_to_child[0]
    c2 = channel_to_child[-1]
    self.assertNotEqual(c1, c2)
    # Test if child light is updated multiplex light is updated as well and vice versa
    c1.power.value[0] = self.dev.power.range[1][0] * 0.5
    self.assertEqual(self.dev.power.value[0], c1.power.value[0])
    c2.power.value[-1] = self.dev.power.range[1][-1] * 0.9
    self.assertEqual(self.dev.power.value[-1], c2.power.value[-1])
    self.dev.power.value[0] = self.dev.power.range[1][0] * 0.2
    self.assertEqual(self.dev.power.value[0], c1.power.value[0])
    self.dev.power.value[-1] = self.dev.power.range[1][-1] * 0.7
    self.assertEqual(self.dev.power.value[-1], c2.power.value[-1])