<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def get_cdpp(self, flux=None):
        '''
        Returns the scalar CDPP for the light curve.

        '''

        if flux is None:
            flux = self.flux
        return self._mission.CDPP(self.apply_mask(flux), cadence=self.cadence)