"And they said, 'No matter what sign you bring us'" meaning: whatever you bring to us; 'mahma' and 'ma' have the same meaning.
﴿وَقَالُوا مهما تأتنا بِهِ﴾ أَيْ: مَا تَأْتِنَا بِهِ: مَهْمَا و (مَا) بِمَعْنى واحدٍ.
