def _stringify(self, transform: StringifyTransform) -> str:
    exprs = [transform(e) for e in self.exprs]
    trailingComma = (',' if self.trailingComma else '')
    return ('{%s%s}' % (', '.join(exprs), trailingComma))
def _stringify(self, transform: StringifyTransform) -> str:
    exprs = [transform(e) for e in self.exprs]
    trailingComma = (',' if self.trailingComma else )
    return ('{%s%s}' % (', '.join(exprs), trailingComma))