code: def test_can_call_a_loader_from_a_loader():
      @Promise.safe
      def do():
          deep_loader, deep_load_calls = id_loader()
          a_loader, a_load_calls = id_loader(
              resolve=lambda keys: deep_loader.load(tuple(keys))
          )
          b_loader, b_load_calls = id_loader(
              resolve=lambda keys: deep_loader.load(tuple(keys))
          )
  
          a1, b1, a2, b2 = Promise.all(
              [
                  a_loader.load("A1"),
                  b_loader.load("B1"),
                  a_loader.load("A2"),
                  b_loader.load("B2"),
              ]
          ).get()
  
          assert a1 == "A1"
          assert b1 == "B1"
          assert a2 == "A2"
          assert b2 == "B2"
  
          assert a_load_calls == [["A1", "A2"]]
          assert b_load_calls == [["B1", "B2"]]
          assert deep_load_calls == [[("A1", "A2"), ("B1", "B2")]]
  
      do().get()
  
imports: from pytest import raises
  from promise import Promise, async_instance
  from promise.dataloader import DataLoader
label_desc: Use image node_id 18 for calling a global function with example usage: test_can_call_a_loader_from_a_loader() without return types