code: def get_data_dtype(self):
      return self.dataobj.dtype
  
file_path: nibabel/nibabel/tests/test_dataobj_images.py
imports: import numpy
  from nibabel.dataobj_images import DataobjImage
  from nibabel.filebasedimages import FileBasedHeader
  from nibabel.tests.test_filebasedimages import TestFBImageAPI
  from nibabel.tests.test_image_api import DataInterfaceMixin
label_desc: Use image node_id 3 for calling the DoNumpyImage obj's underlying member method code with example usage: obj.get_data_dtype() and returns: self