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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 _call_set(self, command, value, *args, **kwargs):
 """ Helper for commands that only set a value to the field. """

        if self.indexable:
            current = self.proxy_get()
            if normalize(current) != normalize(value):
                if current is not None:
                    self.deindex(current)
                if value is not None:
                    self.index(value)
        return self._traverse_command(command, value, *args, **kwargs)