code: def test_preview_unicode_symbol():
      # issue 9107
      a = Symbol("α")
      obj = BytesIO()
      try:
          preview(a, output="png", viewer="BytesIO", outputbuffer=obj)
      except RuntimeError:
          pass
  
file_path: sympy/sympy/printing/tests/test_preview.py
imports: from sympy.core.relational import Eq
  from sympy.core.symbol import Symbol
  from sympy.functions.elementary.piecewise import Piecewise
  from sympy.printing.preview import preview
  from io import BytesIO
label_desc: Use image node_id 2 for calling a global function with example usage: test_preview_unicode_symbol() without return types