code: def test_check_positive(scitype, mtype, fixture_index):
      """Tests that check_is_mtype correctly confirms the mtype of examples.
  
      Parameters
      ----------
      scitype : str - scitype of fixture
      mtype : str - mtype of fixture
      fixture_index : int - index of fixture tuple with that scitype and mtype
  
      Raises
      ------
      RuntimeError if scitype is not defined or has no mtypes or examples
      AssertionError if examples are not correctly identified
      error if check itself raises an error
      """
      # retrieve fixture for checking
      fixture = get_examples(mtype=mtype, as_scitype=scitype).get(
          fixture_index
      )
  
      # todo: possibly remove this once all checks are defined
      check_is_defined = (mtype, scitype) in check_dict.keys()
  
      # check fixtures that exist against checks that exist, when full metadata is queried
      if fixture is not None and check_is_defined:
          check_result = check_is_mtype(
              fixture,
              mtype,
              scitype,
              return_metadata=True,
              msg_return_dict="list",
          )
          if not check_result[0]:
              msg = (
                  f"check_is_mtype returns False on scitype {scitype}, mtype {mtype} "
                  f"fixture {fixture_index}, message: "
              )
              msg = msg + check_result[1]
          assert check_result[0], msg
  
      # check fixtures that exist against checks that exist, when no metadata is queried
      if fixture is not None and check_is_defined:
          check_result = check_is_mtype(
              fixture,
              mtype,
              scitype,
              return_metadata=[],
              msg_return_dict="list",
          )
          if not check_result[0]:
              msg = (
                  f"check_is_mtype returns False on scitype {scitype}, mtype {mtype} "
                  f"fixture {fixture_index}, message: "
              )
              msg = msg + check_result[1]
          assert check_result[0], msg
  
file_path: sktime/sktime/datatypes/tests/test_check.py
imports: import numpy
  from sktime.datatypes._check import AMBIGUOUS_MTYPES, check_dict, check_is_mtype, check_is_scitype
  from sktime.datatypes._check import mtype
  from sktime.datatypes._check import scitype
  from sktime.datatypes._examples import get_examples
  from sktime.datatypes._registry import SCITYPE_LIST, scitype_to_mtype
label_desc: Use image node_id 4 for calling a global function with example usage: test_check_positive(scitype, mtype, fixture_index) without return types