$ grep Client /usr/share/pyshared/glance/client.py
Client classes for callers of a Glance system
class V1Client(base_client.BaseClient):
            c = glance.client.Client(...)
            c = glance.client.Client(...)
            c = glance.client.Client(...)
class ProgressClient(V1Client):
        wrapped = super(ProgressClient, self).image_iterator(connection,
Client = V1Client
        raise exception.ClientConfigurationError(msg)
    client = (ProgressClient if not is_silent_upload else Client)