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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 get_country_name(self, callsign, timestamp=timestamp_now):
 """ Returns the country name where the callsign is located Args: callsign (str):
 Amateur Radio callsign timestamp (datetime, optional):
 datetime in UTC (tzinfo=pytz.UTC) Returns: str: name of the Country Raises: KeyError: No Country found for callsign Note: Don't rely on the country name when working with several instances of py:class:`Callinfo`. Clublog and Country-files.org use slightly different names for countries. Example: - Country-files.com: "Fed. Rep. of Germany" - Clublog: "FEDERAL REPUBLIC OF GERMANY" """

        return self.get_all(callsign, timestamp)[const.COUNTRY]