Orvil hired George to build a house for him. George hired Sherman to put the roof on this new house. Sherman has finished his part, and is afraid that George will not pay him. Sherman doesn't know if George has been paid yet or not. What can Sherman do to protect himself? (Hint- tell me about subcontractor's rights to file a lien affidavit, trapping funds in the hands of owners and the statutory retainage fund.)