code: def _fftfreq_block(i, n, d):
      r = i.copy()
      r[i >= (n + 1) // 2] -= n
      r /= n * d
      return r
  
file_path: dask/dask/array/fft.py
imports: from __future__ import annotations
  import inspect
  from collections.abc import Sequence
  import numpy
  from dask.array.core import asarray
  from dask.array.core import concatenate
  from dask.array.creation import arange
  from dask.utils import derived_from, skip_doctest
label_desc: Use image node_id 7 for calling a global function with example usage: _fftfreq_block(i, n, d) and returns: r