def METHOD_NAME(self, rows):
    'Generate (value, row) for each row in *rows* at this column, excluding null and error values.'
    f = self.sheet.isNullFunc()
    for r in Progress(rows, 'calculating'):
        try:
            v = self.getTypedValue(r)
            if not f(v):
                yield v, r
        except Exception:
            pass