'S3')])

    >>> grades_dtype = [('Name', (np.str_, 10)), ('Marks', np.float64),
    ...                 ('GradeLevel', np.int32)]
    >>> grades_array = np.array([('Sam', 33.3, 3), ('Mike', 44.4, 5),
    ...                         ('Aadi', 66.6, 6)], dtype=grades_dtype)
    >>> np.core.records.fromstring(grades_array.tobytes(), dtype=grades_dtype)
    rec.array([('Sam', 33.3, 3), ('Mike', 44.4, 5), ('Aadi', 66.6, 6)],
            dtype=[('Name', '<U10'), ('Marks', '<f8'), ('GradeLevel', '<i4')])

    >>> s = '\x01\x02\x03abc'
    >>> np.core.records.fromstring(s, dtype='u1,u1,u1,S3')
    Traceback (most recent call last)
       ...
    TypeError: a bytes-like object is required, not 'str'
    Nz2fromstring() needs a 'dtype' or 'formats' argument)