code: def test_repr(self):
      x = provider.ScalarDatum(step=123, wall_time=234.5, value=-0.125)
      repr_ = repr(x)
      self.assertIn(repr(x.step), repr_)
      self.assertIn(repr(x.wall_time), repr_)
      self.assertIn(repr(x.value), repr_)
  
imports: import numpy
  from tensorboard import test
  from tensorboard.data import provider
label_desc: Use image node_id 1 for calling the ScalarDatumTest obj's underlying member method code with example usage: obj.test_repr() without return types