Understanding issorted's lt keyword

[sostock]

@DNF

Where is this made explicit? The closest I could find was

the lt keyword allows providing a custom “less than” function

in the manual, and nothing in the docstring.

That part from the manual is what I meant, and I think it should definitely be added to the docstring.

@DNF

But it does actually accept “lesser than or equal”, since issorted([1,2,2,3]) is true , and that is only sorted if equal is accepted as “less than”.

issorted([1,2,2,3]) uses isless, which is a “lesser than” function, not a “lesser than or equal” function.