deleting a key from a read-only gdbm should be gdbm.error, not KeyError:


>>> import gdbm
>>> db = gdbm.open("foo","n")   # create new
>>> db["a"] = "b"
>>> db.close()
>>> db = gdbm.open("foo","r")   # read only
>>> db["x"] = "1"
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
gdbm.error: Reader can't store    # correct
>>> db["a"]
'b'
>>> del db["a"]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 'a'    # WRONG!  should be the same as above