private Token fetchKey () {
		if (flowLevel == 0) {
			if (!allowSimpleKey) throw new TokenizerException("Found a mapping key where it is not allowed.");
			if (addIndent(column)) tokens.add(Token.BLOCK_MAPPING_START);
		}
		allowSimpleKey = flowLevel == 0;
		forward();
		tokens.add(Token.KEY);
		return Token.KEY;
	}