Allow operator definition syntax to be used for Python operators

[evhub]

Should compile

class A:
    def a + b: ...

to

class A:
    def __add__(a, b): ...

[yggdr]

Would that be made to interoperate with custom operators? Would, in a definition like

operator ~~
def left ~~ right = dostuff(right) - dostuff(left)
class A:
    def left ~~ right: dostuff(right) - left._optimised_dostuff()

the operator defining function (line 2; or rather what it gets compiled down to) be able to first check for the existence of the operator method on left (and then maybe the i-method on right, however that would work syntactically) and call that before falling back to the generic function? Would that maybe even work without line 2, such that there would always be the default operator implementation that checks for such operator methods on its operands, and raises an Exception otherwise?