Returns the number of keys in object o on success, and -1on failure. For objects that do not provide sequence 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()".