Write an integer as an unsigned2 32-bit value.

def write_long(self, n):
        """
        Write an integer as an unsigned2 32-bit value.

        """
        if (n < 0) or (n >= (2**32)):
            raise ValueError('Octet out of range 0..2**31-1')
        self._flushbits()
        self.out.write(pack('>I', n))