code: def test_no_backprop_mode():
      with chainerx.backprop_scope(
          "bp1"
      ) as bp1, chainerx.backprop_scope("bp2") as bp2:
          assert chainerx.is_backprop_required()
          assert chainerx.is_backprop_required(bp1)
          assert chainerx.is_backprop_required(bp2)
  
          with chainerx.no_backprop_mode():
              assert not chainerx.is_backprop_required()
              assert not chainerx.is_backprop_required(bp1)
              assert not chainerx.is_backprop_required(bp2)
          assert chainerx.is_backprop_required()
          assert chainerx.is_backprop_required(bp1)
          assert chainerx.is_backprop_required(bp2)
  
          with chainerx.no_backprop_mode(
              chainerx.get_default_context()
          ):
              assert not chainerx.is_backprop_required()
              assert not chainerx.is_backprop_required(bp1)
              assert not chainerx.is_backprop_required(bp2)
          assert chainerx.is_backprop_required()
          assert chainerx.is_backprop_required(bp1)
          assert chainerx.is_backprop_required(bp2)
  
          with chainerx.no_backprop_mode(bp1):
              assert chainerx.is_backprop_required()
              assert not chainerx.is_backprop_required(bp1)
              assert chainerx.is_backprop_required(bp2)
          assert chainerx.is_backprop_required()
          assert chainerx.is_backprop_required(bp1)
          assert chainerx.is_backprop_required(bp2)
  
          with chainerx.no_backprop_mode((bp1, bp2)):
              assert chainerx.is_backprop_required()
              assert not chainerx.is_backprop_required(bp1)
              assert not chainerx.is_backprop_required(bp2)
          assert chainerx.is_backprop_required()
          assert chainerx.is_backprop_required(bp1)
          assert chainerx.is_backprop_required(bp2)
  
imports: import pytest
  import chainerx
label_desc: Use image node_id 1 for calling a global function with example usage: test_no_backprop_mode() without return types