code: def check_colors(colors):
      """Performs several checks on colors obtained from function colorscale."""
      assert len(colors) == 100
      val, cstring = zip(*colors)
      assert np.allclose(np.linspace(0, 1, 100), val, atol=1e-3)
      assert val[0] == 0
      assert val[-1] == 1
      for cs in cstring:
          assert re.match(r"rgb\(\d+, \d+, \d+\)", cs)
      return val, cstring
  
imports: import base64
  import os
  import re
  import tempfile
  import numpy
  import pytest
  from nilearn.datasets import fetch_surf_fsaverage
  from nilearn.plotting.js_plotting_utils import add_js_lib, colorscale, decode, encode, get_html_template, mesh_to_plotly, to_color_strings
  from nilearn.surface import load_surf_mesh
label_desc: Use image node_id 3 for calling a global function with example usage: check_colors(colors) and returns: val,  cstring