code: def testMergeAllSummaries(self):
      with ops.Graph().as_default():
          const = constant_op.constant(10.0)
          summ1 = summary.histogram("h", const)
          summ2 = summary.scalar("o", const, collections=["foo_key"])
          summ3 = summary.scalar("c", const)
          merge = summary.merge_all()
          self.assertEqual("MergeSummary", merge.op.type)
          self.assertEqual(2, len(merge.op.inputs))
          self.assertEqual(summ1, merge.op.inputs[0])
          self.assertEqual(summ3, merge.op.inputs[1])
          merge = summary.merge_all("foo_key")
          self.assertEqual("MergeSummary", merge.op.type)
          self.assertEqual(1, len(merge.op.inputs))
          self.assertEqual(summ2, merge.op.inputs[0])
          self.assertTrue(summary.merge_all("bar_key") is None)
  
file_path: tensorflow-upstream/tensorflow/python/kernel_tests/summary_ops/summary_v1_ops_test.py
imports: from tensorflow.core.framework import summary_pb2
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import logging_ops
  from tensorflow.python.platform import test
  from tensorflow.python.summary import summary
label_desc: Use image node_id 5 for calling the SummaryV1OpsTest obj's underlying member method code with example usage: obj.testMergeAllSummaries() without return types