docstr: Creates metadata with dummy data.
code: def _create_metadata(self, shape=None):
      """Creates metadata with dummy data."""
      self.name = "unique_name"
      self.display_name = "my mesh"
      self.json_config = "{}"
      if shape is None:
          shape = [1, 100, 3]
      self.shape = shape
      self.components = 14
      self.summary_metadata = metadata.create_summary_metadata(
          self.name,
          self.display_name,
          plugin_data_pb2.MeshPluginData.ContentType.Value("VERTEX"),
          self.components,
          self.shape,
          json_config=self.json_config,
      )
  
file_path: tensorboard/tensorboard/plugins/mesh/metadata_test.py
imports: import tensorflow
  from tensorboard.plugins.mesh import metadata
  from tensorboard.plugins.mesh import plugin_data_pb2
label_desc: Use image node_id 1 for calling the MetadataTest obj's underlying member method code with example usage: obj._create_metadata(shape) without return types