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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 _validate_input_para(self, para, column_names):
 """ Convert the input classificaton para to the correct df column name Parameters para : string column_names : list of strings Returns ------- validated_para : string Converted to the case used in the country file """

        lower_case_valid_class = [et.lower() for et in self.valid_class]

        alt_valid_names = {
            'name_short': ['short', 'short_name', 'name', 'names'],
            'name_official': ['official', 'long_name', 'long'],
            'UNcode': ['un', 'unnumeric'],
            'ISOnumeric': ['isocode'],
            }

        for item in alt_valid_names.items():
            if para.lower() in item[1]:
                para = item[0]

        try:
            validated_para = self.valid_class[
                lower_case_valid_class.index(para.lower())]
        except ValueError:
            raise KeyError(
                '{} is not a valid country classification'.format(para))

        return validated_para