code: def is_parametric_dtype(dtype):
      """Returns True if the dtype is a parametric legacy dtype (itemsize
      is 0, or a datetime without units)
      """
      if dtype.itemsize == 0:
          return True
      if issubclass(dtype.type, (np.datetime64, np.timedelta64)):
          if dtype.name.endswith("64"):
              # Generic time units
              return True
      return False
  
imports: from itertools import permutations, product
  import pytest
  from pytest import param
  import numpy
  from numpy.core._rational_tests import rational
  from numpy.core._multiarray_umath import _discover_array_parameters
  from numpy.testing import assert_array_equal, assert_warns, IS_PYPY
label_desc: Use image node_id 3 for calling a global function with example usage: is_parametric_dtype(dtype) and returns: False, True, True