code: def print_gtk(x, start_viewer=True):
      """Print to Gtkmathview, a gtk widget capable of rendering MathML.
  
      Needs libgtkmathview-bin"""
      with tempfile.NamedTemporaryFile("w") as file:
          file.write(c2p(mathml(x), simple=True))
          file.flush()
  
          if start_viewer:
              subprocess.check_call(("mathmlviewer", file.name))
  
imports: from sympy.printing.mathml import mathml
  from sympy.utilities.mathml import c2p
  import tempfile
  import subprocess
label_desc: Use image node_id 1 for calling a global function with example usage: print_gtk(x, start_viewer) without return types