James was discharged by MegaCorp. He received a letter from MegaCorp offering to pay him double the usual severance pay if he signed a document releasing MegaCorp from all claims he might have had. James signed and dated the release and put it in a mailbox outside the post office. When he returned home, he found he had received a check from MegaCorp in the same amount as offered in the letter. He then returned to the post office, persuaded a postal employee to open the mailbox and retrieved the release. He cashed the check and then filed an age discrimination suit against MegaCorp. Was a contract formed when James put the release in the mailbox