code: def dt_fmt():
      from sys import byteorder
  
      e = "<" if byteorder == "little" else ">"
      return (
          "{{'names':['bool_','uint_','float_','ldbl_'],"
          "'formats':['?','" + e + "u4','" + e + "f4','" + e + "f{}'],"
          "'offsets':[0,4,8,{}],'itemsize':{}}}"
      )
  
imports: import re
  import pytest
  import env
  from pybind11_tests import numpy_dtypes
label_desc: Use image node_id 3 for calling a global function with example usage: dt_fmt() and returns: unknown