private String removeClassSubstring(String string, String substring) {

		int indexofSubstring = string.indexOf(substring);
		if (indexofSubstring == -1) {
			return null;
		}

		if (indexofSubstring + substring.length() >= string.length()) {
			return null;
		}

		String newString = string.substring(indexofSubstring + substring.length());
		if (newString.isBlank() || newString.isEmpty()) {
			return null;
		}

		// should be a space : space and another class name next if gets to here
		if (newString.length() < 4) {
			return null;
		}

		if (newString.indexOf(" : ") == 0) {
			return newString.substring(3);
		}

		return null;

	}
Method to create a graph using pre-configured information found in class structure 
descriptions.
@return the newly created graph
Ghidra/Features/Base/ghidra_scripts/GraphClassesScript.java