'Args:
target, graph, config: same as :meth:`Session.__init__()`.
config: defaults to :func:`tfutils.get_default_sess_config()`'

def __init__(self, target='', graph=None, config=None):

    self.target = target
    if (config is None):
        config = get_default_sess_config()
    self.config = config
    self.graph = graph
