def find_prev_thread_end(buf, (row, col)):
    predicate = lambda line: LineProperties(line).is_diffscuss
    return _find_first(buf, (row, col), predicate, reverse=True)
Returns the row of the end of the previous diffscuss thread, and the
dataset/ETHPy150Open hut8labs/diffscuss/diffscuss/support/editor.py/find_prev_thread_end