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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_continent(self, callsign, timestamp=timestamp_now):
 """ Returns the continent Identifier of a callsign Args: callsign (str):
 Amateur Radio callsign timestamp (datetime, optional):
 datetime in UTC (tzinfo=pytz.UTC) Returns: str: continent identified Raises: KeyError: No Continent found for callsign Note: The following continent identifiers are used: - EU: Europe - NA: North America - SA: South America - AS: Asia - AF: Africa - OC: Oceania - AN: Antarctica """

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