Returns the number of keys in object o on success, and
-1 on failure. For objects that do not provide mapping
protocol, this is equivalent to the Python expression
"len(o)".
On success, return 1 if the mapping object has the key
key and 0 otherwise. This is equivalent to the Python
expression "o.has_key(key)". This function always
succeeds.
Return 1 if the mapping object has the key key and
0 otherwise. This is equivalent to the Python expression
"o.has_key(key)". This function always succeeds.
On success, return a list of the items in object o, where each
item is a tuple containing a key-value pair. On failure, return
NULL. This is equivalent to the Python expression
"o.items()".