code: def test_simple(self):
      state = {
          torchbearer.OPTIMIZER: optim.SGD(
              nn.Linear(10, 10).parameters(), lr=0.01
          )
      }
      metric = LR()
      metric.reset(state)
      self.assertDictEqual(metric.process(state), {"lr": 0.01})
      self.assertDictEqual(metric.process_final(state), {"lr": 0.01})
  
file_path: torchbearer/tests/metrics/test_lr.py
imports: import unittest
  import torch.nn
  import torch.optim
  import torchbearer
  from torchbearer.metrics import LR
label_desc: Use image node_id 1 for calling the TestLR obj's underlying member method code with example usage: obj.test_simple() without return types