code: def ddm_ineg(a: list[list[R]]) -> None:
      """a <-- -a"""
      for ai in a:
          for j, aij in enumerate(ai):
              ai[j] = -aij
  
file_path: sympy/sympy/polys/matrices/dense.py
imports: from __future__ import annotations
  from operator import mul
  from .exceptions import DMShapeError, DMDomainError, DMNonInvertibleMatrixError, DMNonSquareMatrixError
  from typing import Sequence, TypeVar
  from sympy.polys.matrices._typing import RingElement
label_desc: Use image node_id 4 for calling a global function with example usage: ddm_ineg(a) without return types