code: def _generate_scitype_mtype_combinations():
      """Return scitype/mtype tuples for pytest_generate_tests.
  
      Fixtures parameterized
      ----------------------
      scitype : str - scitype of fixture
      mtype : str - mtype of fixture
      """
      # collect fixture tuples here
  
      sci_mtype_tuples = []
  
      for scitype in SCITYPES:
          mtypes = _get_all_mtypes_for_scitype(scitype)
  
          for mtype in mtypes:
              sci_mtype_tuples += [(scitype, mtype)]
  
      return sci_mtype_tuples
  
imports: import numpy
  import pandas
  import pytest
  from sktime.datatypes import MTYPE_REGISTER, SCITYPE_REGISTER
  from sktime.datatypes._check import AMBIGUOUS_MTYPES, check_is_mtype
  from sktime.datatypes._examples import get_examples
  from sktime.datatypes._vectorize import VectorizedDF, _enforce_index_freq
  from sktime.utils._testing.deep_equals import deep_equals
  from sktime.utils.pandas import df_map
  from sktime.utils.parallel import _get_parallel_test_fixtures
label_desc: Use image node_id 3 for calling a global function with example usage: _generate_scitype_mtype_combinations() and returns: sci_mtype_tuples