public void add(String line, int lineNumber) {
			int splitIndex = line.indexOf('=');
			if (splitIndex < 0) {
				error(lineNumber, "Missing required \"=\" for propery line: \"" + line + "\"");
				return;
			}
			String key = line.substring(0, splitIndex).trim();
			String value = line.substring(splitIndex + 1, line.length()).trim();
			if (key.isBlank()) {
				error(lineNumber, "Missing key for propery line: \"" + line + "\"");
				return;
			}
			if (value.isBlank()) {
				error(lineNumber, "Missing value for propery line: \"" + line + "\"");
				return;
			}
			if (properties.containsKey(key)) {
				error(lineNumber, "Duplicate key found in this file!: \"" + key + "\"");
				return;
			}
			properties.put(key, value);
			lineNumbers.put(key, lineNumber);

		}
Adds a raw line from the file to this section. The line will be parsed into a a
key-value pair.
@param line the line to be added/parsed
@param lineNumber the line number in the file for this line
Ghidra/Framework/Gui/src/main/java/generic/theme/AbstractThemeReader.java