code: def test_AssocOp_flatten():
      a, b, c, d = symbols("a,b,c,d")
  
      class MyAssoc(AssocOp):
          identity = S.One
  
      assert (
          MyAssoc(a, MyAssoc(b, c)).args
          == MyAssoc(MyAssoc(a, b), c).args
          == MyAssoc(MyAssoc(a, b, c)).args
          == MyAssoc(a, b, c).args
          == (a, b, c)
      )
      u = MyAssoc(b, c)
      v = MyAssoc(u, d, evaluate=False)
      assert v.args == (u, d)
      # like Add, any unevaluated outer call will flatten inner args
      assert MyAssoc(a, v).args == (a, b, c, d)
  
file_path: sympy/sympy/core/tests/test_operations.py
imports: from sympy.core.expr import Expr
  from sympy.core.numbers import Integer
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol, symbols
  from sympy.core.operations import AssocOp, LatticeOp
  from sympy.testing.pytest import raises
  from sympy.core.sympify import SympifyError
  from sympy.core.add import Add, add
  from sympy.core.mul import Mul, mul
label_desc: Use image node_id 6 for calling a global function with example usage: test_AssocOp_flatten() without return types