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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 _irc_lower(self, in_string):
 """Convert us to our lower-case equivalent, given our std."""

        conv_string = self._translate(in_string)
        if self._lower_trans is not None:
            conv_string = conv_string.translate(self._lower_trans)
        return str.lower(conv_string)