code: def test_empty_match_block():
      # empty match block will not match anything, so it should return a wildcard pattern
      v = relay.Var("v")
      match = relay.Match(v, [])
  
      unmatched = unmatched_cases(match)
      assert len(unmatched) == 1
      assert isinstance(unmatched[0], relay.PatternWildcard)
  
file_path: tvm/tests/python/relay/test_pass_unmatched_cases.py
imports: import tvm
  from tvm import te
  from tvm import relay
  from tvm.relay.prelude import Prelude
  from tvm.relay.analysis import unmatched_cases
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: test_empty_match_block() without return types