class_docstr: Specific Analyze-type array proxy API test
  
  The analyze proxy extends the general API by adding read-only attributes
  ``slope, inter, offset``
code: def validate_dtype(self, pmaker, params):
      # Read-only dtype attribute
      prox, fio, hdr = pmaker()
      assert_dt_equal(prox.dtype, params["dtype"])
      with pytest.raises(AttributeError):
          prox.dtype = np.dtype(prox.dtype)
  
imports: import unittest
  import warnings
  from io import BytesIO
  from itertools import product
  from os.path import join
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_equal
  from ..None import ecat, minc1, minc2, parrec
  from ..analyze import AnalyzeHeader
  from ..arrayproxy import ArrayProxy, is_proxy
  from ..casting import have_binary128, sctypes
  from ..externals.netcdf import netcdf_file
  from ..freesurfer.mghformat import MGHHeader
  from ..nifti1 import Nifti1Header
  from ..optpkg import optional_package
  from ..spm2analyze import Spm2AnalyzeHeader
  from ..spm99analyze import Spm99AnalyzeHeader
  from ..testing import assert_dt_equal, clear_and_catch_warnings
  from ..testing import data_path
  from ..tmpdirs import InTemporaryDirectory
  from ..volumeutils import apply_read_scaling
  from .test_api_validators import ValidateAPI
  from .test_parrec import EG_REC, VARY_REC
label_desc: Use image node_id 2 for calling the TestAnalyzeProxyAPI obj's underlying member method code with example usage: obj.validate_dtype(pmaker, params) without return types