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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 check_street_prefix(self, token):
 """ Finds street prefixes, such as N. or Northwest, before a street name. Standardizes to 1 or two letters, followed by a period. """

        if self.street and not self.street_prefix and token.lower().replace('.', '') in self.parser.prefixes.keys():
            self.street_prefix = self._clean(self.parser.prefixes[token.lower().replace('.', '')])
            return True
        return False