Write a class FormatError for errors in a data format. It extends the built-in SyntaxError. For new FormatError('bad date') the message field is 'bad date' and the name field is 'FormatError'.
new FormatError('bad date').messageReturns 'bad date'
new FormatError('bad date').nameReturns 'FormatError'
new FormatError('bad date') instanceof SyntaxErrorReturns true
Hidden tests run on Submit.