code: def test_solve_lin_sys_2x4_none():
      domain, x1, x2 = ring("x1,x2", QQ)
      eqs = [x1 - 1, x1 - x2, x1 - 2 * x2, x2 - 1]
      assert solve_lin_sys(eqs, domain) is None
  
file_path: sympy/sympy/polys/tests/test_solvers.py
imports: from sympy.matrices import Matrix
  from sympy.polys.domains import ZZ, QQ
  from sympy.polys.fields import field
  from sympy.polys.rings import ring
  from sympy.polys.solvers import solve_lin_sys, eqs_to_matrix
label_desc: Use image node_id 2 for calling a global function with example usage: test_solve_lin_sys_2x4_none() without return types