<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def fit_deriv(x, amplitude, mean, stddev):
 """ GaussianAbsorption1D model function derivatives. """

        import operator
        return list(map(
            operator.neg, Gaussian1D.fit_deriv(x, amplitude, mean, stddev)))