class_docstr: Fake dataset.
docstr: Check contains.
docstr_tok: ["Check","contains","."]
code: def __contains__(self, key):
      """Check contains."""
      return key in self.info or key in self.dims
  
imports: import unittest
  from unittest import mock
  import numpy
  import pytest
  import xarray
label_desc: Use image node_id 3 for calling the FakeDataset obj's underlying member method code with example usage: obj.__contains__(key) and returns: unknown