code: def sample_cache(spark):
      df = spark.read.csv(
          "tests/sample-input.txt", header=True, inferSchema=True
      )
  
      path = "tests/sample-output.sar"
  
      df.coalesce(1).write.format("com.microsoft.sarplus").mode(
          "overwrite"
      ).save(path)
  
      return path
  
imports: import math
  from pathlib import Path
  import numpy
  import pandas
  from pyspark.sql import SparkSession
  import pytest
  from pandas.testing import assert_frame_equal
  from pysarplus import SARPlus, SARModel
label_desc: Use image node_id 3 for calling a global function with example usage: sample_cache(spark) and returns: path