def commonprefix(m):
        if not m: return ''
        s1 = min(m)
        s2 = max(m)
        for i, c in enumerate(s1):
            if c != s2[i]:
                return s1[:i]
        return s1
Given a list of pathnames, returns the longest common leading component
dataset/ETHPy150Open adieu/django-mediagenerator/mediagenerator/filters/less.py/commonprefix