code: def test_repeated_leafs(self):
      a = dict(a=dict(x=1))
      b = dict(a=dict(x=2))
  
      with pytest.raises(ValueError):
          c = utils.merge_params(a, b)
  
imports: from unittest import TestCase
  import pytest
  from elegy import utils
label_desc: Use image node_id 3 for calling the TestMergeStructs obj's underlying member method code with example usage: obj.test_repeated_leafs() without return types