class_docstr: Metrics Plugin for TensorBoard.
code: def _get_invalid_request_error(self, series_request):
      tag = series_request.get("tag")
      plugin = series_request.get("plugin")
      run = series_request.get("run")
      sample = series_request.get("sample")
  
      if not isinstance(tag, str):
          return "Missing tag"
  
      if (
          plugin != scalar_metadata.PLUGIN_NAME
          and plugin != histogram_metadata.PLUGIN_NAME
          and plugin != image_metadata.PLUGIN_NAME
      ):
          return "Invalid plugin"
  
      if plugin in _SINGLE_RUN_PLUGINS and not isinstance(run, str):
          return "Missing run"
  
      if plugin in _SAMPLED_PLUGINS and not isinstance(sample, int):
          return "Missing sample"
  
      return None
  
imports: import collections
  import imghdr
  import json
  from werkzeug import wrappers
  from tensorboard import errors
  from tensorboard import plugin_util
  from tensorboard.backend import http_util
  from tensorboard.data import provider
  from tensorboard.plugins import base_plugin
  from tensorboard.plugins.histogram import metadata
  from tensorboard.plugins.image import metadata
  from tensorboard.plugins.metrics import metadata
  from tensorboard.plugins.scalar import metadata
label_desc: Use image node_id 12 for calling the MetricsPlugin obj's underlying member method code with example usage: obj._get_invalid_request_error(series_request) and returns: None, str, str, str, str