494. Whoever, having a husband or wife living, marries in any case in which such marriage is void by reason of its taking place during the life of such husband or wife, shall be punished with imprisonment of either description for a term which may extend to seven years, and shall also be liable to fine. Exception.- This section does not extend to any person whose marriage with such husband or wife has been declared void by a Court of competent jurisdiction, nor to any person who contracts a marriage during the life of a former husband or wife, if such husband or wife, at the time of the subsequent marriage, shall have been continually absent from such person for the space of seven years, and shall not have been heard of by such person as being alive within that time provided the person contracting such subsequent marriage shall, before such marriage takes place, inform the person with whom such marriage is contracted of the real state of facts so far as the same are within his or her knowledge.