code: def test_SpinParam_reduce():
      dens_u = torch.rand(10)
      dens_d = torch.rand(10)
      sp = SpinParam(u=dens_u, d=dens_d)
  
      def fcn(a, b):
          return a * b
  
      assert torch.all(sp.reduce(fcn).eq(dens_u * dens_d)).item()
  
imports: import pytest
label_desc: Use image node_id 3 for calling a global function with example usage: test_SpinParam_reduce() and returns: unknown