code: def _unpack_simple(fid, dtype, out_dtype):
      """Unpack a NumPy type."""
      dtype = np.dtype(dtype)
      string = fid.read(dtype.itemsize)
      out = np.frombuffer(string, dtype=dtype).astype(out_dtype)
  
      if len(out) > 0:
          out = out[0]
      return out
  
imports: import numpy
  from ..._fiff.utils import read_str
label_desc: Use image node_id 2 for calling a global function with example usage: _unpack_simple(fid, dtype, out_dtype) and returns: out