code: def _matrix_mul(M, v):
      return [sum([row[i] * v[i] for i in range(len(v))]) for row in M]
  
file_path: sympy/sympy/polys/fglmtools.py
imports: from sympy.polys.monomials import monomial_mul, monomial_div
label_desc: Use image node_id 4 for calling a global function with example usage: _matrix_mul(M, v) and returns: unknown