code: def sample_dataset():
      mu = np.arange(1, 7).reshape(2, 3)
      tau = np.arange(7, 13).reshape(2, 3)
  
      chain = [0, 1]
      draws = [0, 1, 2]
  
      data = xr.Dataset(
          {
              "mu": (["chain", "draw"], mu),
              "tau": (["chain", "draw"], tau),
          },
          coords={"draw": draws, "chain": chain},
      )
  
      return mu, tau, data
  
imports: import importlib
  import numpy
  import pytest
  import xarray
  from ...data import from_dict
  from ...plots.backends.matplotlib import dealiase_sel_kwargs, matplotlib_kwarg_dealiaser
  from ...plots.plot_utils import compute_ranks, filter_plotters_list, format_sig_figs, get_plotting_function, make_2d, set_bokeh_circular_ticks_labels, vectorized_to_hex
  from ...rcparams import rc_context
  from ...sel_utils import xarray_sel_iter, xarray_to_ndarray
  from ...stats.density_utils import get_bins
  from ...utils import get_coords
  from ..helpers import running_on_ci
label_desc: Use image node_id 2 for calling a global function with example usage: sample_dataset() and returns: mu,  tau,  data