'Return the names of the subfolders in a given folder
(prefixed with the given folder name).'

def listsubfolders(self, name):

    fullname = os.path.join(self.path, name)
    nlinks = os.stat(fullname).st_nlink
    if (nlinks <= 2):
        return []
    subfolders = []
    subnames = os.listdir(fullname)
    for subname in subnames:
        fullsubname = os.path.join(fullname, subname)
        if os.path.isdir(fullsubname):
            name_subname = os.path.join(name, subname)
            subfolders.append(name_subname)
            nlinks = (nlinks - 1)
            if (nlinks <= 2):
                break
    subfolders.sort()
    return subfolders
