<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def derivative(self, point):
 """Derivative of this operator at ``point``. For the particular case of constant padding with non-zero constant, the derivative is the corresponding zero-padding variant. In all other cases, this operator is linear, i.e. the derivative is equal to ``self``. """

        if self.pad_mode == 'constant' and self.pad_const != 0:
            return ResizingOperator(
                domain=self.domain, range=self.range, pad_mode='constant',
                pad_const=0.0)
        else:  # operator is linear
            return self