Update text with example.

[hameerabbasi]

cc @peterbell10 @rgommers

[peterbell10]

A small thing missing from this backend example is that it will raise KeyError in cases where it should be returning NotImplemented. The fix is here peterbell10@7cd6258.

I would have opened a pull-request but I can’t seem to do it against your fork. Possibly a permission issue?

[peterbell10]

That would be important in calling the default implementations of ones and zeros for example.

[hameerabbasi]

A small thing missing from this backend example is that it will raise KeyError in cases where it should be returning NotImplemented. The fix is here peterbell10@7cd6258.

I would have opened a pull-request but I can’t seem to do it against your fork. Possibly a permission issue?

I can't do it either, weird. Anyway, I merged the changes into my amended commit.