Returns a tuple (deskew angle in degrees, confidence value).

        Returns (None, None) if no angle is available.

def find_skew(self):
        """Returns a tuple (deskew angle in degrees, confidence value).

        Returns (None, None) if no angle is available.
        """
        with _LeptonicaErrorTrap():
            angle = ffi.new('float *', 0.0)
            confidence = ffi.new('float *', 0.0)
            result = lept.pixFindSkew(self._cdata, angle, confidence)
            if result == 0:
                return (angle[0], confidence[0])
            else:
                return (None, None)