code: def pandoc_version():
      """Pandoc's version number"""
      try:
          return pandoc("--version").splitlines()[0].split()[1]
      except OSError:
          return "N/A"
  
file_path: jupytext/src/jupytext/pandoc.py
imports: import os
  import subprocess
  import tempfile
  from nbformat import reads
  from nbformat import writes
  from packaging.version import parse
label_desc: Use image node_id 4 for calling a global function with example usage: pandoc_version() and returns: pandoc, str