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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_suffix(self, token):
 """ Attempts to match a street suffix. If found, it will return the abbreviation, with the first letter capitalized and a period after it. E.g. "St." or "Ave." """

        # Suffix must come before street
        # print "Suffix check", token, "suffix", self.street_suffix, "street", self.street
        if self.street_suffix is None and self.street is None:
            # print "upper", token.upper()
            if token.upper() in self.parser.suffixes.keys():
                suffix = self.parser.suffixes[token.upper()]
                self.street_suffix = self._clean(suffix.capitalize() + '.')
                return True
            elif token.upper() in self.parser.suffixes.values():
                self.street_suffix = self._clean(token.capitalize() + '.')
                return True
        return False