Return a copy of self with the sign bit unset.

        Unlike abs(self), this does not make use of the context: the result
        has the same precision as the original.

def copy_abs(self):
        """ Return a copy of self with the sign bit unset.

        Unlike abs(self), this does not make use of the context: the result
        has the same precision as the original.

        """
        result = mpfr.Mpfr_t.__new__(BigFloat)
        mpfr.mpfr_init2(result, self.precision)
        mpfr.mpfr_setsign(result, self, False, ROUND_TIES_TO_EVEN)
        return result