dump as a comma separated value file

def DumpAsCSV (self, separator=",", file=sys.stdout):
                """dump as a comma separated value file"""
                for row in range(1, self.maxRow + 1):
                        sep = ""
                        for column in range(1, self.maxColumn + 1):
                                file.write("%s\"%s\"" % (sep, self.GetCellValue(column, row, "")))
                                sep = separator
                        file.write("\n")