Drools Extension Error

package com.tester;

import java.util.ArrayList;
import java.util.List;

import com.tester.*;

rule "ruleA"
    when
        $contract : Contract( $isTeamContract : teamContract)
        (or
            $employee : Employee ($isTeamContract == false)
            $employee : Employee ($isTeamContract == true)
        )
    then
end

rule "ruleB"
    extends "ruleA"
    when
        $secondsInWeek : Number( ) from accumulate(
           ShiftAssignment( $seconds : shiftDurationSeconds)
            sum($seconds)
        )

    then
        int secondsMissing = $secondsInWeek.intValue();
end