Help to combine: ReduceLROnPlateau + OneCycleLR (CosineAnnealingLR)

Good afternoon. Help to combine the two chedulers (I can’t do it) ReduceLROnPlateau + OneCycleLR (CosineAnnealingLR)

optimizer = torch.optim.Adam(model.parameters(), lr=LR)
scheduler = torch.optim.lr_scheduler.ReduceLROnPlateau(
optimizer,
factor=0.7,
patience=scheduler_N,
threshold=1e-10,
verbose=True)
LR_shed = []
max_lr = LR/0.7
for epoch in range(model_epoch_start, model_epoch_end):
scheduler_b = torch.optim.lr_scheduler.OneCycleLR(
optimizer,
max_lr=max_lr,
total_steps=len(train),
pct_start=0.3,
cycle_momentum=False)
for x, y in train:

model.train()

model.eval()

LR_shed.append(optimizer.param_groups[0][‘lr’])
scheduler_b.step()

scheduler.step(loss_val)
max_lr = scheduler._last_lr[0]/0.7

plt.plot(LR_shed)

work example: ReduceLROnPlateau + OneCycleLR

Help me