'Find a path in this folder, where path is a
tuple of folder and file names like (\'eBooks\', \'newest\',
\'calibre.epub\'). Finding is case-insensitive.'

def find_path(self, path):

    parent = self
    components = list(path)
    while components:
        child = components[0]
        components = components[1:]
        c = parent.folder_named(child)
        if (c is None):
            c = parent.file_named(child)
        if (c is None):
            return None
        parent = c
    return parent
