LambdaLR
class torch.optim.lr_scheduler.LambdaLR(optimizer, lr_lambda, last_epoch=- 1, verbose=False)
Sets the learning rate of each parameter group to the initial lr
   times a given function. When last_epoch=-1, sets initial lr as lr.
Parameters:
      * optimizer (Optimizer) -- Wrapped optimizer.
  * **lr_lambda** (*function** or **list*) -- A function which
    computes a multiplicative factor given an integer parameter
    epoch, or a list of such functions, one for each group in
    optimizer.param_groups.

  * **last_epoch** (*int*) -- The index of last epoch. Default:
    -1.

  * **verbose** (*bool*) -- If "True", prints a message to stdout
    for each update. Default: "False".

-[ Example ]-



Assuming optimizer has two groups.
lambda1 = lambda epoch: epoch // 30
lambda2 = lambda epoch: 0.95 ** epoch
scheduler = LambdaLR(optimizer, lr_lambda=[lambda1, lambda2])
for epoch in range(100):


