code: def test_promote_dtypes_basic(self):
      assert (
          type_mapping.promote_dtypes([types.int32, types.int32])
          == types.int32
      )
      assert (
          type_mapping.promote_dtypes(
              [types.int32, types.int64, types.int16]
          )
          == types.int64
      )
      assert (
          type_mapping.promote_dtypes(
              [types.fp16, types.fp32, types.fp64]
          )
          == types.fp64
      )
      assert (
          type_mapping.promote_dtypes(
              [types.fp16, types.int32, types.int64]
          )
          == types.fp16
      )
  
imports: import pytest
  from coremltools.converters.mil.mil import types
  from coremltools.converters.mil.mil.types import type_mapping
label_desc: Use image node_id 1 for calling the TestTypeMapping obj's underlying member method code with example usage: obj.test_promote_dtypes_basic() without return types