def get_a_copy(self, row):
"""
Take a copy of a certain book.
"""
if int(self.table.item(row, 5).text()) > 0:
book = Library.take_book(self.generate_book_by_row(row))
item = QtGui.QTableWidgetItem(str(book.number_of_copies))
self.table.setItem(row, 5, item)
