def _generate_limit_items(lower, upper):
<EOL>if lower is not None and upper is not None and lower == upper:<EOL><INDENT>yield '<STR_LIT>', upper + <NUM_LIT:0><EOL><DEDENT>else:<EOL><INDENT>if lower is not None:<EOL><INDENT>yield '<STR_LIT>', lower + <NUM_LIT:0><EOL><DEDENT>if upper is not None:<EOL><INDENT>yield '<STR_LIT>', upper + <NUM_LIT:0><EOL><DEDENT><DEDENT>
Yield key, value pairs for limits dictionary.

    Yield pairs of key, value where key is ``lower``, ``upper`` or ``fixed``.
    A key, value pair is emitted if the bounds are not None.