Forgery consists of filling in blanks on a document containing a genuine signature, or materially altering or erasing an existing instrument. An underlying intent to defraud, based on knowledge of the false nature of the instrument, must accompany the act. Instruments of forgery may include bills of exchange, bills of lading, promissory notes, checks, bonds, receipts, orders for money or goods, mortgages, discharges of mortgages, deeds, public records, account books, and certain kinds of tickets or passes for transportation or events. Statutes define forgery as a felony. Punishment generally consists of a fine or imprisonment, or both. Methods of forgery include handwriting, printing, engraving, and typewriting. The related crime of uttering a forged document occurs when an inauthentic writing is intentionally offered as genuine. Some modern statutes include this crime with forgery.