code: def commonprefix(m):
      "Given a list of pathnames, returns the longest common leading component"
      if not m: return ''
      s1 = min(m)
      s2 = max(m)
      for i, c in enumerate(s1):
          if c != s2[i]:
              return s1[:i]
      return sf commonprefix(m):
      "Given a list of pathnames, returns the longest common leading component"
      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
docs: Given a list of pathnames, returns the longest common leading component