final TypeRegistry typeRegistry = context.getTypeRegistry();
final Number n1 = typeRegistry.convertToNumber(parameters.getType(0), parameters.getValue(0));
final Number n2 = typeRegistry.convertToNumber(parameters.getType(1), parameters.getValue(1));
final Number n3 = typeRegistry.convertToNumber(parameters.getType(2), parameters.getValue(2));
if (n1 == null || n2 == null || n3 == null)
{
throw EvaluationException.getInstance(
LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);