code: def test_indexing_drops_references(self):
      fp = memmap(
          self.tmpfp, dtype=self.dtype, mode="w+", shape=self.shape
      )
      tmp = fp[(1, 2), (2, 3)]
      if isinstance(tmp, memmap):
          assert_(tmp._mmap is not fp._mmap)
  
imports: import sys
  import os
  import mmap
  import pytest
  from pathlib import Path
  from tempfile import NamedTemporaryFile, TemporaryFile
  from numpy import memmap, sum, average, prod, ndarray, isscalar, add, subtract, multiply
  from numpy import arange, allclose, asarray
  from numpy.testing import assert_, assert_equal, assert_array_equal, suppress_warnings, IS_PYPY, break_cycles
label_desc: Use image node_id 13 for calling the TestMemmap obj's underlying member method code with example usage: obj.test_indexing_drops_references() without return types