The trustee is an officer of the court, appointed to examine the debtor, collect the debtor’s nonexempt property, and pay the expenses of the estate and the claims of creditors. In addition, the trustee has certain administrative duties in a chapter 7 case and is the officer in charge of seeing to it that the debtor performs the required duties in the case. A trustee is appointed in a chapter 7 case, even if the debtor has no nonexempt property.