}
if (!(pDerivation.value instanceof ListValue))
throw new RuntimeException("Derivation value is not a list: " + pDerivation.value);
ListValue list = (ListValue) pDerivation.value;
if (Formulas.isCountFormula(pDerivation.formula)) {
if (list.values.size() != 1) {
throw new RuntimeException(
"Evaluation of count formula " + pDerivation.formula + " has size " + list.values.size());
}