'Initializer for GpuParamServerDeviceSetter.
Args:
worker_device: the device to use for computation Ops.
ps_devices: a list of devices to use for Variable Ops. Each variable is
assigned to the least loaded device.'

def __init__(self, worker_device, ps_devices):

    self.ps_devices = ps_devices
    self.worker_device = worker_device
    self.ps_sizes = ([0] * len(self.ps_devices))
