code: def fake_coeff_from_fn(fn):
      """Create Fake Coefficients."""
      ameans = np.random.uniform(261, 267, N_CHANNEL)
      locations = [
          [1, 2],
          [1, 2],
          [3, 4, 5],
          [3, 4, 5],
          [4, 5, 6],
          [5, 6, 7],
          [6, 7, 8],
          [7, 8],
          [9, 10, 11],
          [10, 11],
          [10, 11, 12],
          [11, 12, 13],
          [12, 13],
          [12, 13, 14],
          [14, 15],
          [1, 16],
          [17, 18],
          [18, 19],
          [18, 19, 20],
          [19, 20, 21],
          [20, 21, 22],
          [21, 22],
      ]
      all_nchx = [len(loc) for loc in locations]
  
      coeff_str = []
      for idx in range(1, N_CHANNEL + 1):
          nx = idx - 1
          coeff_str.append("\n")
          next_line = "   {}  {} {}\n".format(
              idx, all_nchx[nx], ameans[nx]
          )
          coeff_str.append(next_line)
          next_line = "   {}\n".format(
              "   ".join([str(x) for x in locations[idx - 1]])
          )
          coeff_str.append(next_line)
          for fov in range(1, N_FOV + 1):
              random_coeff = np.ones(all_nchx[nx])
              str_coeff = "  ".join([str(x) for x in random_coeff])
              random_means = np.zeros(all_nchx[nx])
              str_means = " ".join([str(x) for x in random_means])
              error_val = np.random.uniform(0, 4)
              coeffs_line = " {:>2} {:>2}  {} {}   {}\n".format(
                  idx, fov, str_coeff, str_means, error_val
              )
              coeff_str.append(coeffs_line)
  
      return coeff_str
  
imports: from __future__ import annotations
  import os
  from datetime import datetime
  from unittest import mock
  import numpy
  import pytest
  import xarray
  from satpy._config import config_search_paths
  from satpy.dataset import DataID
  from satpy.readers import load_reader
  from satpy.readers.yaml_reader import FileYAMLReader
label_desc: Use image node_id 1 for calling a global function with example usage: fake_coeff_from_fn(fn) and returns: coeff_str