Tryton application platform - account invoice correction module

 Tryton is a high-level general purpose application platform. It is the base
 of a complete business solution as well as a comprehensive health and hospital
 information system (GNUHealth).
 .
 The account invoice correction module adds a wizard on invoice which allows
 select lines for which the unit price must be corrected.
 A new invoice is created with those lines in double: once with the original
 quantity, once with the inverted quantity.