def _set_missing_to_none(self, currency):
rates = self._rates[currency]<EOL>first_date, last_date = self.bounds[currency]<EOL>for date in list_dates_between(first_date, last_date):<EOL><INDENT>if date not in rates:<EOL><INDENT>rates[date] = None<EOL><DEDENT><DEDENT>if self.verbose:<EOL><INDENT>missing = len([r for r in itervalues(rates) if r is None])<EOL>if missing:<EOL><INDENT>print('<STR_LIT>'.format(<EOL>currency, missing, first_date, last_date,<EOL><NUM_LIT:1> + (last_date - first_date).days))<EOL><DEDENT><DEDENT>
Fill missing rates of a currency with the closest available ones.