code: def spectral_angle_mapper() -> tuple:
      """Plot spectral angle mapper example."""
      from torchmetrics.image.sam import SpectralAngleMapper
  
      gen = torch.manual_seed(42)
      p = lambda: torch.rand([16, 3, 16, 16], generator=gen)
      t = lambda: torch.rand([16, 3, 16, 16], generator=gen)
  
      # plot single value
      metric = SpectralAngleMapper()
      metric.update(p(), t())
      fig, ax = metric.plot()
  
      # plot multiple values
      metric = SpectralAngleMapper()
      vals = [metric(p(), t()) for _ in range(10)]
      fig, ax = metric.plot(vals)
  
      return fig, ax
  
imports: import argparse
  import matplotlib.pyplot
  import torch
label_desc: Use image node_id 14 for calling a global function with example usage: spectral_angle_mapper() and returns: fig,  ax