'Bridge the runtime gap between the work factor supplied in `encoded`
and the work factor suggested by this hasher.
Taking PBKDF2 as an example, if `encoded` contains 20000 iterations and
`self.iterations` is 30000, this method should run password through
another 10000 iterations of PBKDF2. Similar approaches should exist
for any hasher that has a work factor. If not, this method should be
defined as a no-op to silence the warning.'

def harden_runtime(self, password, encoded):

    warnings.warn('subclasses    of    BasePasswordHasher    should    provide    a    harden_runtime()    method')
