code: def test_pipeline_fixed_merger_input():
      accumulator = Accumulate()
  
      pipeline = Pipeline(max_loops_allowed=10)
      pipeline.add_component(
          "merge", MergeLoop(expected_type=int, inputs=["in_1", "in_2"])
      )
      pipeline.add_component("below_10", Threshold(threshold=10))
      pipeline.add_component("accumulator", accumulator)
      pipeline.add_component("add_two", AddFixedValue(add=2))
  
      pipeline.connect("merge.value", "below_10.value")
      pipeline.connect("below_10.below", "accumulator.value")
      pipeline.connect("accumulator.value", "merge.in_2")
      pipeline.connect("below_10.above", "add_two.value")
  
      results = pipeline.run({"merge": {"in_1": 4}})
      assert results == {"add_two": {"result": 18}}
      assert accumulator.state == 16
  
imports: from haystack.core.pipeline import Pipeline
  from haystack.testing.sample_components import Accumulate, AddFixedValue, Threshold, MergeLoop, FirstIntSelector
  import logging
label_desc: Use image node_id 3 for calling a global function with example usage: test_pipeline_fixed_merger_input() without return types