[ ESuper (EIdentifier "x") (ENumber "1")
, ESymbol Bin "+"
, ESuper (EIdentifier "x") (EIdentifier "a")
, ESymbol Bin "+"
, ESuper (EIdentifier "H") (EIdentifier "a")
, ESymbol Bin "+"
, ESuper (EIdentifier "H") (ENumber "1")
]