code: def _sample_color(
      strategy: str,
      rng: np.random.RandomState,
  ) -> Tuple[Optional[str], kb.Color]:
      """Samples an object's color.
  
      Args:
        strategy: Sampling strategy.
        rng: Source of randomness.
  
      Returns:
        color_label: Human-readable description of "color".
        color: Kubric color for this object.
      """
      # Note: If you add an option here, update COLOR_STRATEGIES as well.
      if strategy in ["black", "gray", "white"]:
          return strategy, kb.get_color(strategy)
      elif strategy == "clevr":
          color_label = rng.choice(list(COLORS.keys()))
          return color_label, COLORS[color_label]
      elif strategy == "uniform":
          return None, kb.random_hue_color(rng=rng)
      else:
          raise ValueError(
              f"Unknown color sampling strategy {strategy}"
          )
  
file_path: kubric/challenges/robust_nerf/worker.py
imports: import collections
  import json
  import logging
  from typing import Dict, List, Optional, Tuple
  import kubric
  import kubric.renderer.blender
  import kubric.simulator.pybullet
  import numpy
  import tensorflow
  import bpy
label_desc: Use image node_id 2 for calling a global function with example usage: _sample_color(strategy, rng) and returns: strategy,  kb, color_label,  COLORS, None,  kb