code: def test_drop_metadata_identity_and_copy(dtype):
      # If there is no metadata, the identity is preserved:
      assert _utils_impl.drop_metadata(dtype) is dtype
  
      # If there is any, it is dropped (subforms are checked above)
      dtype = np.dtype(dtype, metadata={1: 2})
      assert _utils_impl.drop_metadata(dtype).metadata is None
  
file_path: numpy/numpy/lib/tests/test_utils.py
imports: import pytest
  import numpy
  from numpy.testing import assert_raises_regex
  import numpy.lib._utils_impl
  from io import StringIO
label_desc: Use image node_id 4 for calling a global function with example usage: test_drop_metadata_identity_and_copy(dtype) without return types