code: def test_SpinParam_sum():
      dens_u = torch.rand(10)
      dens_d = torch.rand(10)
      sp = SpinParam(u=dens_u, d=dens_d)
  
      assert torch.all(sp.sum().eq(dens_u + dens_d)).item()
  
imports: import pytest
label_desc: Use image node_id 2 for calling a global function with example usage: test_SpinParam_sum() without return types