'unbind() -> int
unbind_s() -> None
unbind_ext() -> int
unbind_ext_s() -> None
This call is used to unbind from the directory, terminate
the current association, and free resources. Once called, the
connection to the LDAP server is closed and the LDAP object
is invalid. Further invocation of methods on the object will
yield an exception.
The unbind and unbind_s methods are identical, and are
synchronous in nature'

def unbind_ext(self, serverctrls=None, clientctrls=None):

    return self._ldap_call(self._l.unbind_ext, EncodeControlTuples(serverctrls), EncodeControlTuples(clientctrls))
