code: def is_combining(sym):
      """Check whether symbol is a unicode modifier."""
  
      return ord(sym) in _remove_combining
  
imports: import sys
  import warnings
  from string import ascii_lowercase, ascii_uppercase
  import unicodedata
  from sympy.printing.conventions import split_super_sub
  from sympy.core.alphabets import greeks
  from sympy.utilities.exceptions import sympy_deprecation_warning
label_desc: Use image node_id 12 for calling a global function with example usage: is_combining(sym) and returns: unknown