<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def convex_conj(self):
 """The conjugate functional of IndicatorLpUnitBall. The convex conjugate functional of an ``Lp`` norm, ``p < infty`` is the indicator function on the unit ball defined by the corresponding dual norm ``q``, given by ``1/p + 1/q = 1`` and where ``q = infty`` if ``p = 1`` [Roc1970]. By the Fenchel-Moreau theorem, the convex conjugate functional of indicator function on the unit ball in ``Lq`` is the corresponding Lp-norm [BC2011]. References [Roc1970] Rockafellar, R. T. *Convex analysis*. Princeton University Press, 1970. [BC2011] Bauschke, H H, and Combettes, P L. *Convex analysis and monotone operator theory in Hilbert spaces*. Springer, 2011. """

        if self.exponent == np.inf:
            return L1Norm(self.domain)
        elif self.exponent == 2:
            return L2Norm(self.domain)
        else:
            return LpNorm(self.domain, exponent=conj_exponent(self.exponent))