def _der(self, x):
    '\n        Returns the first derivative of the interpolated function at each value\n        in x. Only called internally by HARKinterpolator1D.derivative (etc).\n        '
    return self._evalOrDer(x, False, True)[0]
Returns the first derivative of the interpolated function at each value
in x. Only called internally by HARKinterpolator1D.derivative (etc).
def _der(self, x):
    '\n        Returns the first derivative of the interpolated function at each value\n        in x. Only called internally by HARKinterpolator1D.derivative (etc).\n        '
    return self._evalOrDer(x, False, True)[0]