function getQualifier(sTerm, sExpectedTerm) {
		if (sTerm === sExpectedTerm) {
			return "";
		}
		if (sTerm.startsWith(sExpectedTerm) && sTerm[sExpectedTerm.length] === "#"
				&& !sTerm.includes("@", sExpectedTerm.length)) {
			return sTerm.slice(sExpectedTerm.length + 1);
		}
	}
Checks that the term is the expected term and determines the qualifier.

@param {string} sTerm
  The term
@param {string} sExpectedTerm
  The expected term
@returns {string|undefined}
  The qualifier or <code>undefined</code>, if the term is not the expected term