def METHOD_NAME(cls, fparser2_tree):
    '''Extract the datatype and access metadata from the fparser2 tree and
    return them as strings. Also check that the metadata is in the
    expected form (but do not check the metadata values as that is
    done separately).
    :param fparser2_tree: fparser2 tree containing the metadata \
        for this argument.
    :type fparser2_tree: :py:class:`fparser.two.Fortran2003.Part_Ref` | \
        :py:class:`fparser.two.Fortran2003.Structure_Constructor`
    :returns: a tuple containing the datatype and access metadata.
    :rtype: Tuple[str, str]
    '''
    cls.check_fparser2_arg(fparser2_tree, "arg_type")
    cls.check_nargs(fparser2_tree)
    cls.check_first_arg(fparser2_tree)
    datatype = cls.get_arg(fparser2_tree, cls.datatype_arg_index)
    access = cls.get_arg(fparser2_tree, cls.access_arg_index)
    return (datatype, access)