def __str__(self):
        if self.table.formatting.has_key(self.column_name):
            func = self.table.formatting[self.column_name].get('filter', None)
            args = self.table.formatting[self.column_name].get('args', [])
            kwargs = self.table.formatting[self.column_name].get('options', {})
            if func:
                row = self.table[self.row_num]
                args = [row[arg].value for arg in args]
                return format(self.value, func, *args, **kwargs)
        return self.value
Calling str(datum) should check first for a formatted
dataset/ETHPy150Open eyeseast/python-tablefu/table_fu/__init__.py/Datum.__str__