def METHOD_NAME(self, column_name, result, line):
    result = str(result)
    if result.startswith('--') or result == '' or result == 'ND':
        return 0.0
    try:
        result = float(result)
        if result < 0.0:
            result = 0.0
    except ValueError:
        self.err(
            "No valid number ${result} in column (${column_name})",
            mapping={"result": result,
                     "column_name": column_name},
            numline=self._numline, line=line)
        return
    return result