cbook alltrue() and onetrue()

Here's the code from cbook.py

def alltrue(seq):
    #return true if all elements of seq are true. If seq is empty return false
    if not len(seq): return False
    for val in seq:
        if not seq: return False
    return True

def onetrue(seq):
    #return true if one elements of seq are true. If seq is empty return false
    if not len(seq): return False
    for val in seq:
        if seq: return True
    return False

They do not work as intended, for example:

alltrue([False])

True

onetrue([False])

True

I think they should be
        if not val: return False
        if val: return True

However, it looks like onetrue() is never used and alltrue() is used in
lines.py and backend_ps.py, but is imported from numerix not cbook - so
can these cookbook functions be deleted?

Regards
Steve