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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_user_columns_list(self):
 """ Returns all model's columns except pk or fk """

        ret_lst = list()
        for col_name in self.get_columns_list():
            if (not self.is_pk(col_name)) and (not self.is_fk(col_name)):
                ret_lst.append(col_name)
        return ret_lst