@typecheck_method(fields=sequenceof(sized_tupleof(str, IR)))
def __init__(self, fields):
    super().__init__(*[ir for (n, ir) in fields])
    self.fields = fields
@typecheck_method(fields=sequenceof(sized_tupleof(str, IR)))
def __init__(self, fields):
    super().__init__(*[ir for (n, ir) in fields])
    self.fields = fields