:func:`deepspeed.initialize` returns a training engine in its first argument of type :class:`DeepSpeedEngine`. This engine is used to progress training:
for step, batch in enumerate(data_loader):
#forward() method
loss = model_engine(batch)
#runs backpropagation
model_engine.backward(loss)
#weight update
model_engine.step().. autofunction:: deepspeed.DeepSpeedEngine.forward
.. autofunction:: deepspeed.DeepSpeedEngine.backward
.. autofunction:: deepspeed.DeepSpeedEngine.step
.. autofunction:: deepspeed.DeepSpeedEngine.is_gradient_accumulation_boundary