type arity0('a) = {I0: unit => 'a,
};type arity1('a) = {I1: 'a,
};type arity2('a) = {I2: 'a,
};type arity3('a) = {I3: 'a,
};type arity4('a) = {I4: 'a,
};type arity5('a) = {I5: 'a,
};type arity6('a) = {I6: 'a,
};type arity7('a) = {I7: 'a,
};type arity8('a) = {I8: 'a,
};type arity9('a) = {I9: 'a,
};type arity10('a) = {I10: 'a,
};type arity11('a) = {I11: 'a,
};type arity12('a) = {I12: 'a,
};type arity13('a) = {I13: 'a,
};type arity14('a) = {I14: 'a,
};type arity15('a) = {I15: 'a,
};type arity16('a) = {I16: 'a,
};type arity17('a) = {I17: 'a,
};type arity18('a) = {I18: 'a,
};type arity19('a) = {I19: 'a,
};type arity20('a) = {I20: 'a,
};type arity21('a) = {I21: 'a,
};type arity22('a) = {I22: 'a,
};