code: def istuple(node):
      return isinstance(node, ast.Tuple)
  
file_path: catboost/contrib/python/pythran/pythran/optimizations/tuple_to_shape.py
imports: from pythran.analyses import Aliases
  from pythran.tables import MODULES
  from pythran.passmanager import Transformation
  from pythran.utils import pythran_builtin_attr
  import gast
label_desc: Use image node_id 1 for calling a global function with example usage: istuple(node) and returns: isinstance