// We put a fake Constraint element in the stack that can take either math, notes or message.
// This a hack to be able to read some mathMl or notes by themselves.
if (currentNode.getLocalPart().equals("notes") || currentNode.getLocalPart().equals("message")) {
initializedParsers.put("", new SBMLCoreParser());
} else if (currentNode.getLocalPart().equals("math")) {
initializedParsers.put("", new MathMLStaxParser());
initializedParsers.put(ASTNode.URI_MATHML_DEFINITION, new MathMLStaxParser());