code: def uunion1d(arr1, arr2):
      
      v = np.union1d(arr1, arr2)
      v = _validate_numpy_wrapper_units(v, [arr1, arr2])
      return v
docs: Find the union of two arrays.
  
      A wrapper around numpy.intersect1d that preserves units.  All input arrays
      must have the same units.  See the documentation of numpy.intersect1d for
      full details.
  
      Examples
      --------
      >>> from unyt import cm
      >>> A = [1, 2, 3]*cm
      >>> B = [2, 3, 4]*cm
      >>> uunion1d(A, B)
      unyt_array([1, 2, 3, 4], 'cm')